Only start a fading animation if we're visible. And a threadsafety fix.
Only start a fading animation if we're visible. And a threadsafety fix.

aaronschubert0/AsyncDisplayKit,garrettmoon/AsyncDisplayKit,levi/AsyncDisplayKit,hannahmbanana/AsyncDisplayKit,eanagel/AsyncDisplayKit,george-gw/AsyncDisplayKit,Adlai-Holler/AsyncDisplayKit,yufenglv/AsyncDisplayKit,facebook/AsyncDisplayKit,JetZou/AsyncDisplayKit,aaronschubert0/AsyncDisplayKit,Adlai-Holler/AsyncDisplayKit,jellenbogen/AsyncDisplayKit,hannahmbanana/AsyncDisplayKit,rmls/AsyncDisplayKit,gazreese/AsyncDisplayKit,bimawa/AsyncDisplayKit,bimawa/AsyncDisplayKit,levi/AsyncDisplayKit,hannahmbanana/AsyncDisplayKit,smyrgl/AsyncDisplayKit,nrcmedia/AsyncDisplayKit,lappp9/AsyncDisplayKit,jellenbogen/AsyncDisplayKit,eanagel/AsyncDisplayKit,maicki/AsyncDisplayKit,nrcmedia/AsyncDisplayKit,Adlai-Holler/AsyncDisplayKit,jellenbogen/AsyncDisplayKit,lappp9/AsyncDisplayKit,Xinchi/AsyncDisplayKit,nrcmedia/AsyncDisplayKit,chrisdanford/AsyncDisplayKit,george-gw/AsyncDisplayKit,nrcmedia/AsyncDisplayKit,tomizimobile/AsyncDisplayKit,facebook/AsyncDisplayKit,facebook/AsyncDisplayKit,tomizimobile/AsyncDisplayKit,levi/AsyncDisplayKit,chrisdanford/AsyncDisplayKit,bimawa/AsyncDisplayKit,marmelroy/AsyncDisplayKit,Xinchi/AsyncDisplayKit,gazreese/AsyncDisplayKit,maicki/AsyncDisplayKit,tomizimobile/AsyncDisplayKit,samhsiung/AsyncDisplayKit,smyrgl/AsyncDisplayKit,tomizimobile/AsyncDisplayKit,levi/AsyncDisplayKit,Xinchi/AsyncDisplayKit,yufenglv/AsyncDisplayKit,samhsiung/AsyncDisplayKit,rmls/AsyncDisplayKit,rahul-malik/AsyncDisplayKit,gazreese/AsyncDisplayKit,aaronschubert0/AsyncDisplayKit,yufenglv/AsyncDisplayKit,rmls/AsyncDisplayKit,marmelroy/AsyncDisplayKit,romyilano/AsyncDisplayKit,JetZou/AsyncDisplayKit,lappp9/AsyncDisplayKit,romyilano/AsyncDisplayKit,marmelroy/AsyncDisplayKit,rcancro/AsyncDisplayKit,harryworld/AsyncDisplayKit,lappp9/AsyncDisplayKit,garrettmoon/AsyncDisplayKit,rcancro/AsyncDisplayKit,garrettmoon/AsyncDisplayKit,samhsiung/AsyncDisplayKit,rahul-malik/AsyncDisplayKit,harryworld/AsyncDisplayKit,jellenbogen/AsyncDisplayKit,chrisdanford/AsyncDisplayKit,smyrgl/AsyncDisplayKit,eanagel/AsyncDisplayKit,marmelroy/AsyncDisplayKit,maicki/AsyncDisplayKit,aaronschubert0/AsyncDisplayKit,rahul-malik/AsyncDisplayKit,JetZou/AsyncDisplayKit,JetZou/AsyncDisplayKit,hannahmbanana/AsyncDisplayKit,rmls/AsyncDisplayKit,jellenbogen/AsyncDisplayKit,tomizimobile/AsyncDisplayKit,romyilano/AsyncDisplayKit,Adlai-Holler/AsyncDisplayKit,Adlai-Holler/AsyncDisplayKit,flovouin/AsyncDisplayKit,Xinchi/AsyncDisplayKit,rcancro/AsyncDisplayKit,nrcmedia/AsyncDisplayKit,harryworld/AsyncDisplayKit,george-gw/AsyncDisplayKit,garrettmoon/AsyncDisplayKit,hannahmbanana/AsyncDisplayKit,harryworld/AsyncDisplayKit,rcancro/AsyncDisplayKit,flovouin/AsyncDisplayKit,flovouin/AsyncDisplayKit,yufenglv/AsyncDisplayKit,flovouin/AsyncDisplayKit,gazreese/AsyncDisplayKit,rmls/AsyncDisplayKit,facebook/AsyncDisplayKit,smyrgl/AsyncDisplayKit,yufenglv/AsyncDisplayKit,levi/AsyncDisplayKit,rcancro/AsyncDisplayKit,maicki/AsyncDisplayKit,bimawa/AsyncDisplayKit,harryworld/AsyncDisplayKit,maicki/AsyncDisplayKit,garrettmoon/AsyncDisplayKit,aaronschubert0/AsyncDisplayKit,eanagel/AsyncDisplayKit,JetZou/AsyncDisplayKit,eanagel/AsyncDisplayKit,flovouin/AsyncDisplayKit,rahul-malik/AsyncDisplayKit,chrisdanford/AsyncDisplayKit,romyilano/AsyncDisplayKit,george-gw/AsyncDisplayKit,Xinchi/AsyncDisplayKit,samhsiung/AsyncDisplayKit