auto merge of #547 : brson/servo/alert, r=metajack
auto merge of #547 : brson/servo/alert, r=metajack

Depends on https://github.com/mozilla-servo/rust-alert/pull/2

snf/servo,ruud-v-a/servo,Adenilson/prototype-viewing-distance,nerith/servo,CJ8664/servo,nnethercote/servo,dsandeephegde/servo,KiChjang/servo,peterjoel/servo,eddyb/servo,KiChjang/servo,szeged/servo,Aalhad/CanvasRenderingContext2DMozilla,seanmonstar/servo,A-deLuna/servo,emilio/servo,bjwbell/servo,jdramani/servo,runarberg/servo,walac/servo,pyfisch/servo,dsandeephegde/servo,sadmansk/servo,A-deLuna/servo,emilio/servo,kindersung/servo,peterjoel/servo,wpgallih/servo,evilpie/servo,paulrouget/servo,s142857/servo,Aalhad/CanvasRenderingContext2DMozilla,dmarcos/servo,hyowon/servo,eddyb/servo,splav/servo,ConnorGBrewster/servo,KiChjang/servo,vks/servo,wpgallih/servo,pyfisch/servo,thiagopnts/servo,chotchki/servo,mattnenterprise/servo,mt2d2/servo,rixrix/servo,pyfisch/servo,canaltinova/servo,aweinstock314/servo,dmarcos/servo,tempbottle/servo,mrobinson/servo,pyecs/servo,DominoTree/servo,dati91/servo,snf/servo,pyfisch/servo,RenaudParis/servo,DominoTree/servo,pyfisch/servo,WriterOfAlicrow/servo,Shraddha512/servo,notriddle/servo,notriddle/servo,nerith/servo,pgonda/servo,samfoo/servo,boghison/servo,j3parker/servo,boghison/servo,jgraham/servo,nnethercote/servo,emilio/servo,wartman4404/servo,larsbergstrom/servo,mattnenterprise/servo,nerith/servo,rnestler/servo,brson/servo,splav/servo,huonw/servo,froydnj/servo,deokjinkim/servo,rnestler/servo,indykish/servo,tschneidereit/servo,dmarcos/servo,GreenRecycleBin/servo,GreenRecycleBin/servo,jdramani/servo,metajack/servo,Adenilson/prototype-viewing-distance,seanmonstar/servo,huonw/servo,pcwalton/servo,KiChjang/servo,SimonSapin/servo,anthgur/servo,caldwell/servo,dagnir/servo,boghison/servo,DominoTree/servo,steveklabnik/servo,peterjoel/servo,metajack/servo,brson/servo,dagnir/servo,meh/servo,echochamber/servo,boghison/servo,larsbergstrom/servo,nick-thompson/servo,thiagopnts/servo,kindersung/servo,ConnorGBrewster/servo,michaelwu/servo,WriterOfAlicrow/servo,DominoTree/servo,canaltinova/servo,anthgur/servo,srbhklkrn/SERVOENGINE,froydnj/servo,tschneidereit/servo,notriddle/servo,peterjoel/servo,zhangjunlei26/servo,ryancanhelpyou/servo,rixrix/servo,aweinstock314/servo,jlegendary/servo,CJ8664/servo,pcwalton/servo,canaltinova/servo,nerith/servo,vks/servo,avadacatavra/servo,deokjinkim/servo,froydnj/servo,aidanhs/servo,dvberkel/servo,huonw/servo,upsuper/servo,notriddle/servo,j3parker/servo,zentner-kyle/servo,juzer10/servo,akosel/servo,eddyb/servo,zentner-kyle/servo,deokjinkim/servo,mt2d2/servo,nick-thompson/servo,indykish/servo,pgonda/servo,Adenilson/prototype-viewing-distance,jgraham/servo,jdramani/servo,s142857/servo,evilpie/servo,metajack/servo,zhangjunlei26/servo,bjwbell/servo,wpgallih/servo,brendandahl/servo,wartman4404/servo,walac/servo,mattnenterprise/servo,fiji-flo/servo,ryancanhelpyou/servo,Shraddha512/servo,mdibaiee/servo,aidanhs/servo,samfoo/servo,dvberkel/servo,emilio/servo,paulrouget/servo,rentongzhang/servo,SimonSapin/servo,aidanhs/servo,j3parker/servo,A-deLuna/servo,dati91/servo,j3parker/servo,splav/servo,froydnj/servo,walac/servo,emilio/servo,brendandahl/servo,peterjoel/servo,upsuper/servo,emilio/servo,mrobinson/servo,GyrosOfWar/servo,bjwbell/servo,kindersung/servo,peterjoel/servo,ruud-v-a/servo,brson/servo,tempbottle/servo,mrobinson/servo,szeged/servo,pyfisch/servo,dsandeephegde/servo,RenaudParis/servo,fiji-flo/servo,dati91/servo,youprofit/servo,pgonda/servo,kindersung/servo,nick-thompson/servo,notriddle/servo,codemac/servo,deokjinkim/servo,GreenRecycleBin/servo,owaspjocur/servo,owaspjocur/servo,GreenRecycleBin/servo,bfrohs/servo,cbrewster/servo,karlito40/servo,tafia/servo,dhananjay92/servo,jlegendary/servo,splav/servo,tempbottle/servo,rixrix/servo,huonw/servo,notriddle/servo,nrc/servo,dmarcos/servo,huonw/servo,mt2d2/servo,Aalhad/CanvasRenderingContext2DMozilla,Adenilson/prototype-viewing-distance,juzer10/servo,mdibaiee/servo,upsuper/servo,paulrouget/servo,SimonSapin/servo,avadacatavra/servo,evilpie/servo,mbrubeck/servo,nerith/servo,codemac/servo,chotchki/servo,wartman4404/servo,paulrouget/servo,notriddle/servo,mattnenterprise/servo,thiagopnts/servo,rentongzhang/servo,sadmansk/servo,jlegendary/servo,DominoTree/servo,akosel/servo,nnethercote/servo,pyecs/servo,thiagopnts/servo,mbrubeck/servo,splav/servo,rixrix/servo,wpgallih/servo,pyecs/servo,RenaudParis/servo,hyowon/servo,KiChjang/servo,srbhklkrn/SERVOENGINE,saneyuki/servo,pgonda/servo,metajack/servo,g-k/servo,karlito40/servo,pgonda/servo,GreenRecycleBin/servo,eddyb/servo,s142857/servo,dvberkel/servo,echochamber/servo,brendandahl/servo,juzer10/servo,saneyuki/servo,eddyb/servo,tafia/servo,youprofit/servo,mt2d2/servo,mdibaiee/servo,fiji-flo/servo,mt2d2/servo,thiagopnts/servo,pyfisch/servo,akosel/servo,jlegendary/servo,caldwell/servo,pgonda/servo,metajack/servo,wartman4404/servo,saratang/servo,ruud-v-a/servo,brendandahl/servo,rentongzhang/servo,shrenikgala/servo,canaltinova/servo,luniv/servo,jimberlage/servo,luniv/servo,vks/servo,RenaudParis/servo,dsandeephegde/servo,bjwbell/servo,shrenikgala/servo,froydnj/servo,huonw/servo,pyecs/servo,emilio/servo,juzer10/servo,rixrix/servo,tschneidereit/servo,dvberkel/servo,RenaudParis/servo,szeged/servo,dmarcos/servo,tafia/servo,zentner-kyle/servo,bjwbell/servo,tempbottle/servo,seanmonstar/servo,dhananjay92/servo,emilio/servo,walac/servo,Aalhad/CanvasRenderingContext2DMozilla,szeged/servo,nick-thompson/servo,A-deLuna/servo,kindersung/servo,shrenikgala/servo,saneyuki/servo,CJ8664/servo,srbhklkrn/SERVOENGINE,dati91/servo,boghison/servo,paulrouget/servo,GyrosOfWar/servo,szeged/servo,luniv/servo,codemac/servo,pyecs/servo,akosel/servo,brendandahl/servo,samfoo/servo,saneyuki/servo,WriterOfAlicrow/servo,mt2d2/servo,snf/servo,karlito40/servo,akosel/servo,meh/servo,caldwell/servo,boghison/servo,mattnenterprise/servo,codemac/servo,dvberkel/servo,wpgallih/servo,larsbergstrom/servo,mattnenterprise/servo,AnthonyBroadCrawford/servo,tafia/servo,mukilan/servo,dsandeephegde/servo,youprofit/servo,GreenRecycleBin/servo,AnthonyBroadCrawford/servo,szeged/servo,canaltinova/servo,cbrewster/servo,ConnorGBrewster/servo,rentongzhang/servo,nick-thompson/servo,pcwalton/servo,youprofit/servo,michaelwu/servo,seanmonstar/servo,rentongzhang/servo,karlito40/servo,steveklabnik/servo,jimberlage/servo,owaspjocur/servo,wpgallih/servo,seanmonstar/servo,larsbergstrom/servo,nerith/servo,rentongzhang/servo,steveklabnik/servo,avadacatavra/servo,rixrix/servo,g-k/servo,upsuper/servo,j3parker/servo,emilio/servo,AnthonyBroadCrawford/servo,deokjinkim/servo,dhananjay92/servo,tempbottle/servo,youprofit/servo,splav/servo,upsuper/servo,DominoTree/servo,walac/servo,saneyuki/servo,dmarcos/servo,runarberg/servo,aweinstock314/servo,luniv/servo,aidanhs/servo,nick-thompson/servo,zhangjunlei26/servo,wpgallih/servo,j3parker/servo,nnethercote/servo,thiagopnts/servo,peterjoel/servo,hyowon/servo,mrobinson/servo,saratang/servo,ruud-v-a/servo,aidanhs/servo,mukilan/servo,pyecs/servo,ryancanhelpyou/servo,canaltinova/servo,pcwalton/servo,WriterOfAlicrow/servo,zhangjunlei26/servo,hyowon/servo,juzer10/servo,shrenikgala/servo,michaelwu/servo,owaspjocur/servo,KiChjang/servo,mukilan/servo,samfoo/servo,kindersung/servo,CJ8664/servo,saneyuki/servo,youprofit/servo,zhangjunlei26/servo,chotchki/servo,akosel/servo,emilio/servo,bfrohs/servo,karlito40/servo,brson/servo,walac/servo,rnestler/servo,Aalhad/CanvasRenderingContext2DMozilla,anthgur/servo,mdibaiee/servo,codemac/servo,ruud-v-a/servo,indykish/servo,shrenikgala/servo,szeged/servo,runarberg/servo,AnthonyBroadCrawford/servo,echochamber/servo,SimonSapin/servo,hyowon/servo,jimberlage/servo,AnthonyBroadCrawford/servo,boghison/servo,nnethercote/servo,dhananjay92/servo,nrc/servo,DominoTree/servo,upsuper/servo,pyfisch/servo,snf/servo,deokjinkim/servo,dmarcos/servo,jlegendary/servo,AnthonyBroadCrawford/servo,rnestler/servo,fiji-flo/servo,samfoo/servo,tschneidereit/servo,peterjoel/servo,eddyb/servo,WriterOfAlicrow/servo,brson/servo,anthgur/servo,notriddle/servo,bfrohs/servo,evilpie/servo,ConnorGBrewster/servo,runarberg/servo,paulrouget/servo,echochamber/servo,mukilan/servo,snf/servo,zentner-kyle/servo,anthgur/servo,pyfisch/servo,mdibaiee/servo,sadmansk/servo,bfrohs/servo,echochamber/servo,fiji-flo/servo,nnethercote/servo,tempbottle/servo,larsbergstrom/servo,indykish/servo,DominoTree/servo,michaelwu/servo,mt2d2/servo,saneyuki/servo,DominoTree/servo,indykish/servo,dsandeephegde/servo,larsbergstrom/servo,Shraddha512/servo,avadacatavra/servo,jimberlage/servo,jimberlage/servo,wartman4404/servo,eddyb/servo,sadmansk/servo,GreenRecycleBin/servo,fiji-flo/servo,steveklabnik/servo,ConnorGBrewster/servo,g-k/servo,vks/servo,owaspjocur/servo,meh/servo,vks/servo,splav/servo,brendandahl/servo,pcwalton/servo,KiChjang/servo,A-deLuna/servo,indykish/servo,saneyuki/servo,aidanhs/servo,srbhklkrn/SERVOENGINE,caldwell/servo,jimberlage/servo,GyrosOfWar/servo,caldwell/servo,bfrohs/servo,sadmansk/servo,upsuper/servo,GyrosOfWar/servo,ryancanhelpyou/servo,WriterOfAlicrow/servo,dagnir/servo,dvberkel/servo,rnestler/servo,GreenRecycleBin/servo,thiagopnts/servo,rnestler/servo,saratang/servo,larsbergstrom/servo,deokjinkim/servo,Shraddha512/servo,dsandeephegde/servo,RenaudParis/servo,jgraham/servo,caldwell/servo,evilpie/servo,jlegendary/servo,runarberg/servo,mbrubeck/servo,canaltinova/servo,michaelwu/servo,owaspjocur/servo,rixrix/servo,peterjoel/servo,nerith/servo,g-k/servo,nrc/servo,peterjoel/servo,metajack/servo,DominoTree/servo,froydnj/servo,aweinstock314/servo,fiji-flo/servo,mukilan/servo,wartman4404/servo,paulrouget/servo,GreenRecycleBin/servo,chotchki/servo,jgraham/servo,KiChjang/servo,mbrubeck/servo,juzer10/servo,tempbottle/servo,juzer10/servo,codemac/servo,mattnenterprise/servo,GyrosOfWar/servo,vks/servo,paulrouget/servo,meh/servo,Shraddha512/servo,aweinstock314/servo,dvberkel/servo,ryancanhelpyou/servo,larsbergstrom/servo,bjwbell/servo,indykish/servo,tafia/servo,szeged/servo,karlito40/servo,mbrubeck/servo,mdibaiee/servo,nrc/servo,echochamber/servo,saratang/servo,steveklabnik/servo,s142857/servo,wpgallih/servo,zhangjunlei26/servo,hyowon/servo,nrc/servo,tschneidereit/servo,runarberg/servo,cbrewster/servo,g-k/servo,ruud-v-a/servo,saneyuki/servo,dsandeephegde/servo,larsbergstrom/servo,A-deLuna/servo,splav/servo,evilpie/servo,jlegendary/servo,samfoo/servo,rnestler/servo,cbrewster/servo,avadacatavra/servo,huonw/servo,runarberg/servo,fiji-flo/servo,dagnir/servo,shrenikgala/servo,mbrubeck/servo,Adenilson/prototype-viewing-distance,bjwbell/servo,splav/servo,paulrouget/servo,paulrouget/servo,dati91/servo,ConnorGBrewster/servo,rixrix/servo,szeged/servo,steveklabnik/servo,zentner-kyle/servo,srbhklkrn/SERVOENGINE,sadmansk/servo,SimonSapin/servo,canaltinova/servo,SimonSapin/servo,mattnenterprise/servo,zhangjunlei26/servo,dagnir/servo,mrobinson/servo,meh/servo,ConnorGBrewster/servo,luniv/servo,thiagopnts/servo,zentner-kyle/servo,CJ8664/servo,Aalhad/CanvasRenderingContext2DMozilla,aweinstock314/servo,SimonSapin/servo,shrenikgala/servo,SimonSapin/servo,KiChjang/servo,mukilan/servo,jgraham/servo,CJ8664/servo,jgraham/servo,upsuper/servo,dhananjay92/servo,pyecs/servo,chotchki/servo,zhangjunlei26/servo,s142857/servo,jimberlage/servo,meh/servo,michaelwu/servo,nrc/servo,avadacatavra/servo,indykish/servo,tafia/servo,pgonda/servo,g-k/servo,pyfisch/servo,avadacatavra/servo,steveklabnik/servo,meh/servo,mdibaiee/servo,nnethercote/servo,hyowon/servo,luniv/servo,rentongzhang/servo,jgraham/servo,mbrubeck/servo,saneyuki/servo,GyrosOfWar/servo,g-k/servo,jdramani/servo,evilpie/servo,pcwalton/servo,GyrosOfWar/servo,echochamber/servo,eddyb/servo,tafia/servo,jdramani/servo,notriddle/servo,bfrohs/servo,jimberlage/servo,dati91/servo,jdramani/servo,youprofit/servo,Shraddha512/servo,codemac/servo,nnethercote/servo,vks/servo,WriterOfAlicrow/servo,zhangjunlei26/servo,aidanhs/servo,dati91/servo,nnethercote/servo,wpgallih/servo,cbrewster/servo,samfoo/servo,A-deLuna/servo,srbhklkrn/SERVOENGINE,CJ8664/servo,akosel/servo,splav/servo,anthgur/servo,saratang/servo,nrc/servo,jimberlage/servo,anthgur/servo,dagnir/servo,saratang/servo,caldwell/servo,mbrubeck/servo,indykish/servo,cbrewster/servo,rnestler/servo,dati91/servo,dhananjay92/servo,cbrewster/servo,jdramani/servo,mrobinson/servo,dhananjay92/servo,larsbergstrom/servo,sadmansk/servo,AnthonyBroadCrawford/servo,avadacatavra/servo,evilpie/servo,KiChjang/servo,cbrewster/servo,nick-thompson/servo,ryancanhelpyou/servo,notriddle/servo,Adenilson/prototype-viewing-distance,Adenilson/prototype-viewing-distance,brendandahl/servo,s142857/servo,brson/servo,seanmonstar/servo,dagnir/servo,CJ8664/servo,saratang/servo,evilpie/servo,tschneidereit/servo,Shraddha512/servo,anthgur/servo,RenaudParis/servo,kindersung/servo,ryancanhelpyou/servo,szeged/servo,snf/servo,s142857/servo,rixrix/servo,snf/servo,sadmansk/servo,zentner-kyle/servo,aweinstock314/servo,j3parker/servo,luniv/servo,chotchki/servo,ConnorGBrewster/servo,srbhklkrn/SERVOENGINE,wartman4404/servo,walac/servo,nnethercote/servo,tschneidereit/servo,karlito40/servo