Remove ffmpeg dependency from appveyor
Remove ffmpeg dependency from appveyor

KiChjang/servo,avadacatavra/servo,nnethercote/servo,peterjoel/servo,pyfisch/servo,jimberlage/servo,szeged/servo,larsbergstrom/servo,mbrubeck/servo,peterjoel/servo,paulrouget/servo,KiChjang/servo,SimonSapin/servo,peterjoel/servo,ConnorGBrewster/servo,fiji-flo/servo,jimberlage/servo,paulrouget/servo,ConnorGBrewster/servo,upsuper/servo,CJ8664/servo,emilio/servo,anthgur/servo,SimonSapin/servo,fiji-flo/servo,eddyb/servo,eddyb/servo,mattnenterprise/servo,splav/servo,canaltinova/servo,pyfisch/servo,KiChjang/servo,canaltinova/servo,emilio/servo,KiChjang/servo,rnestler/servo,larsbergstrom/servo,ConnorGBrewster/servo,dati91/servo,emilio/servo,dsandeephegde/servo,paulrouget/servo,nnethercote/servo,fiji-flo/servo,pyfisch/servo,SimonSapin/servo,nnethercote/servo,paulrouget/servo,szeged/servo,nnethercote/servo,thiagopnts/servo,SimonSapin/servo,nnethercote/servo,szeged/servo,jimberlage/servo,peterjoel/servo,canaltinova/servo,sadmansk/servo,splav/servo,notriddle/servo,fiji-flo/servo,splav/servo,larsbergstrom/servo,paulrouget/servo,dati91/servo,paulrouget/servo,larsbergstrom/servo,splav/servo,mbrubeck/servo,rnestler/servo,sadmansk/servo,avadacatavra/servo,CJ8664/servo,jimberlage/servo,anthgur/servo,saneyuki/servo,SimonSapin/servo,mbrubeck/servo,splav/servo,paulrouget/servo,anthgur/servo,dsandeephegde/servo,upsuper/servo,cbrewster/servo,pyfisch/servo,DominoTree/servo,eddyb/servo,jimberlage/servo,upsuper/servo,emilio/servo,mattnenterprise/servo,notriddle/servo,thiagopnts/servo,mattnenterprise/servo,eddyb/servo,DominoTree/servo,emilio/servo,emilio/servo,avadacatavra/servo,splav/servo,mbrubeck/servo,sadmansk/servo,peterjoel/servo,paulrouget/servo,jimberlage/servo,splav/servo,ConnorGBrewster/servo,canaltinova/servo,SimonSapin/servo,dati91/servo,KiChjang/servo,saneyuki/servo,jimberlage/servo,CJ8664/servo,dati91/servo,cbrewster/servo,avadacatavra/servo,sadmansk/servo,SimonSapin/servo,thiagopnts/servo,larsbergstrom/servo,DominoTree/servo,rnestler/servo,cbrewster/servo,saneyuki/servo,saneyuki/servo,dsandeephegde/servo,eddyb/servo,canaltinova/servo,dsandeephegde/servo,peterjoel/servo,nnethercote/servo,mbrubeck/servo,DominoTree/servo,larsbergstrom/servo,ConnorGBrewster/servo,mattnenterprise/servo,peterjoel/servo,sadmansk/servo,notriddle/servo,ConnorGBrewster/servo,KiChjang/servo,DominoTree/servo,CJ8664/servo,szeged/servo,nnethercote/servo,upsuper/servo,mbrubeck/servo,ConnorGBrewster/servo,eddyb/servo,cbrewster/servo,CJ8664/servo,dsandeephegde/servo,notriddle/servo,saneyuki/servo,upsuper/servo,mattnenterprise/servo,eddyb/servo,fiji-flo/servo,avadacatavra/servo,emilio/servo,anthgur/servo,cbrewster/servo,avadacatavra/servo,CJ8664/servo,fiji-flo/servo,rnestler/servo,paulrouget/servo,saneyuki/servo,pyfisch/servo,larsbergstrom/servo,splav/servo,fiji-flo/servo,cbrewster/servo,upsuper/servo,emilio/servo,pyfisch/servo,thiagopnts/servo,canaltinova/servo,splav/servo,larsbergstrom/servo,dsandeephegde/servo,dsandeephegde/servo,notriddle/servo,DominoTree/servo,peterjoel/servo,saneyuki/servo,DominoTree/servo,KiChjang/servo,rnestler/servo,larsbergstrom/servo,dsandeephegde/servo,nnethercote/servo,sadmansk/servo,eddyb/servo,larsbergstrom/servo,szeged/servo,szeged/servo,szeged/servo,thiagopnts/servo,anthgur/servo,fiji-flo/servo,pyfisch/servo,DominoTree/servo,KiChjang/servo,notriddle/servo,canaltinova/servo,saneyuki/servo,mattnenterprise/servo,anthgur/servo,pyfisch/servo,szeged/servo,jimberlage/servo,notriddle/servo,emilio/servo,DominoTree/servo,mbrubeck/servo,cbrewster/servo,emilio/servo,szeged/servo,jimberlage/servo,ConnorGBrewster/servo,canaltinova/servo,CJ8664/servo,mbrubeck/servo,anthgur/servo,rnestler/servo,KiChjang/servo,notriddle/servo,anthgur/servo,peterjoel/servo,thiagopnts/servo,notriddle/servo,cbrewster/servo,avadacatavra/servo,pyfisch/servo,sadmansk/servo,upsuper/servo,mattnenterprise/servo,peterjoel/servo,SimonSapin/servo,avadacatavra/servo,rnestler/servo,notriddle/servo,DominoTree/servo,CJ8664/servo,dati91/servo,nnethercote/servo,splav/servo,pyfisch/servo,saneyuki/servo,paulrouget/servo,thiagopnts/servo,sadmansk/servo,saneyuki/servo,KiChjang/servo,mattnenterprise/servo,rnestler/servo,upsuper/servo,nnethercote/servo,dati91/servo,dati91/servo,dati91/servo,thiagopnts/servo,szeged/servo