signals: Add missing signals
signals: Add missing signals

Note that the `pages_*` names are plural , while the `article_*` names
are singular.  I'll fix this once I update the PagesGenerator.

number5/pelican,ls2uper/pelican,crmackay/pelican,rbarraud/pelican,alexras/pelican,11craft/pelican,JeremyMorgan/pelican,garbas/pelican,karlcow/pelican,UdeskDeveloper/pelican,HyperGroups/pelican,janaurka/git-debug-presentiation,Rogdham/pelican,karlcow/pelican,jimperio/pelican,sunzhongwei/pelican,Polyconseil/pelican,alexras/pelican,number5/pelican,JeremyMorgan/pelican,gymglish/pelican,catdog2/pelican,gymglish/pelican,kernc/pelican,HyperGroups/pelican,Rogdham/pelican,lucasplus/pelican,ehashman/pelican,joetboole/pelican,eevee/pelican,levanhien8/pelican,abrahamvarricatt/pelican,Summonee/pelican,abrahamvarricatt/pelican,fbs/pelican,btnpushnmunky/pelican,jimperio/pelican,ingwinlu/pelican,deved69/pelican-1,HyperGroups/pelican,0xMF/pelican,florianjacob/pelican,simonjj/pelican,Scheirle/pelican,goerz/pelican,lucasplus/pelican,lazycoder-ru/pelican,douglaskastle/pelican,Scheirle/pelican,jo-tham/pelican,talha131/pelican,iKevinY/pelican,TC01/pelican,Summonee/pelican,kennethlyn/pelican,GiovanniMoretti/pelican,jimperio/pelican,number5/pelican,getpelican/pelican,iurisilvio/pelican,liyonghelpme/myBlog,GiovanniMoretti/pelican,arty-name/pelican,lazycoder-ru/pelican,UdeskDeveloper/pelican,ionelmc/pelican,crmackay/pelican,farseerfc/pelican,TC01/pelican,catdog2/pelican,kernc/pelican,ls2uper/pelican,koobs/pelican,liyonghelpme/myBlog,lucasplus/pelican,goerz/pelican,11craft/pelican,jvehent/pelican,levanhien8/pelican,ls2uper/pelican,Scheirle/pelican,koobs/pelican,avaris/pelican,talha131/pelican,treyhunner/pelican,crmackay/pelican,jvehent/pelican,simonjj/pelican,btnpushnmunky/pelican,eevee/pelican,Summonee/pelican,joetboole/pelican,ingwinlu/pelican,garbas/pelican,iKevinY/pelican,GiovanniMoretti/pelican,ehashman/pelican,janaurka/git-debug-presentiation,joetboole/pelican,avaris/pelican,liyonghelpme/myBlog,11craft/pelican,florianjacob/pelican,treyhunner/pelican,liyonghelpme/myBlog,TC01/pelican,51itclub/pelican,catdog2/pelican,lazycoder-ru/pelican,jo-tham/pelican,getpelican/pelican,51itclub/pelican,alexras/pelican,deanishe/pelican,liyonghelpme/myBlog,kennethlyn/pelican,goerz/pelican,rbarraud/pelican,zackw/pelican,kernc/pelican,51itclub/pelican,sunzhongwei/pelican,abrahamvarricatt/pelican,florianjacob/pelican,justinmayer/pelican,btnpushnmunky/pelican,eevee/pelican,simonjj/pelican,zackw/pelican,deanishe/pelican,JeremyMorgan/pelican,UdeskDeveloper/pelican,gymglish/pelican,jvehent/pelican,Polyconseil/pelican,sunzhongwei/pelican,deanishe/pelican,deved69/pelican-1,iurisilvio/pelican,sunzhongwei/pelican,garbas/pelican,iurisilvio/pelican,Rogdham/pelican,douglaskastle/pelican,janaurka/git-debug-presentiation,douglaskastle/pelican,ehashman/pelican,farseerfc/pelican,koobs/pelican,karlcow/pelican,zackw/pelican,deved69/pelican-1,rbarraud/pelican,kennethlyn/pelican,levanhien8/pelican,treyhunner/pelican