Dispatch lazy image downloaders to another thread
Dispatch lazy image downloaders to another thread

fixes #148

maicki/AsyncDisplayKit,flovouin/AsyncDisplayKit,Cen92/AsyncDisplayKit,bimawa/AsyncDisplayKit,nivanchikov/AsyncDisplayKit,PodsMakleso6/AsyncDisplayKit,rcancro/AsyncDisplayKit,paulyoung/AsyncDisplayKit,DanielAsher/AsyncDisplayKit,jflinter/AsyncDisplayKit,rahul-malik/AsyncDisplayKit,gazreese/AsyncDisplayKit,yangyangluoluo/AsyncDisplayKit,ppamorim/AsyncDisplayKit,eanagel/AsyncDisplayKit,meitianapp/AsyncDisplayKit,romyilano/AsyncDisplayKit,facebook/AsyncDisplayKit,RuiAAPeres/AsyncDisplayKit,k1ok3n/AsyncDisplayKit,zeitgeist7/AsyncDisplayKit,gazreese/AsyncDisplayKit,nrcmedia/AsyncDisplayKit,Teino1978-Corp/Teino1978-Corp-AsyncDisplayKit,k1ok3n/AsyncDisplayKit,facebook/AsyncDisplayKit,angi2/AsyncDisplayKit,zeyang101909/AsyncDisplayKit,wangjiangwen/AsyncDisplayKit,supriyantomaftuh/AsyncDisplayKit,ERussel/AsyncDisplayKit,Adlai-Holler/AsyncDisplayKit,benzguo/AsyncDisplayKit,harryworld/AsyncDisplayKit,kesiking/AsyncDisplayKit,codepython/AsyncDisplayKit,PodsMakleso6/AsyncDisplayKit,flovouin/AsyncDisplayKit,wangjiangwen/AsyncDisplayKit,levi/AsyncDisplayKit,ppamorim/AsyncDisplayKit,flovouin/AsyncDisplayKit,zeyang101909/AsyncDisplayKit,nivanchikov/AsyncDisplayKit,xujim/AsyncDisplayKit,garrettmoon/AsyncDisplayKit,rahul-malik/AsyncDisplayKit,hejunbinlan/AsyncDisplayKit,zhangyabinzyb/AsyncDisplayKit,aaronschubert0/AsyncDisplayKit,hbucius/AsyncDisplayKit,xujim/AsyncDisplayKit,JetZou/AsyncDisplayKit,lappp9/AsyncDisplayKit,200895045/AsyncDisplayKit,k1ok3n/AsyncDisplayKit,michaelvillar/AsyncDisplayKit,tharhtet/AsyncDisplayKit,angi2/AsyncDisplayKit,zdw19840929/AsyncDisplayKit,harryworld/AsyncDisplayKit,mtxs007/AsyncDisplayKit,angi2/AsyncDisplayKit,grgcombs/AsyncDisplayKit,smyrgl/AsyncDisplayKit,hejunbinlan/AsyncDisplayKit,hannahmbanana/AsyncDisplayKit,Teino1978-Corp/Teino1978-Corp-AsyncDisplayKit,george-gw/AsyncDisplayKit,NghiaTranUIT/AsyncDisplayKit,donpark/AsyncDisplayKit,zhangyabinzyb/AsyncDisplayKit,zdw19840929/AsyncDisplayKit,hbucius/AsyncDisplayKit,dvan001/AsyncDisplayKit,yangyangluoluo/AsyncDisplayKit,PodsMakleso6/AsyncDisplayKit,yangyangluoluo/AsyncDisplayKit,romyilano/AsyncDisplayKit,eanagel/AsyncDisplayKit,todotodoo/AsyncDisplayKit,benzguo/AsyncDisplayKit,facebook/AsyncDisplayKit,treejames/AsyncDisplayKit,tharhtet/AsyncDisplayKit,21451061/AsyncDisplayKit,adamdahan/AsyncDisplayKit,Cen92/AsyncDisplayKit,skullacy/AsyncDisplayKit,Xinchi/AsyncDisplayKit,yufenglv/AsyncDisplayKit,jellenbogen/AsyncDisplayKit,Adlai-Holler/AsyncDisplayKit,steveram/AsyncDisplayKit,samhsiung/AsyncDisplayKit,owenwuef/AsyncDisplayKit,meitianapp/AsyncDisplayKit,samhsiung/AsyncDisplayKit,steveram/AsyncDisplayKit,ERussel/AsyncDisplayKit,donpark/AsyncDisplayKit,jflinter/AsyncDisplayKit,kesiking/AsyncDisplayKit,skullacy/AsyncDisplayKit,romyilano/AsyncDisplayKit,Xinchi/AsyncDisplayKit,ppamorim/AsyncDisplayKit,skullacy/AsyncDisplayKit,hannahmbanana/AsyncDisplayKit,maicki/AsyncDisplayKit,ERussel/AsyncDisplayKit,rmls/AsyncDisplayKit,nrcmedia/AsyncDisplayKit,zeyang101909/AsyncDisplayKit,supriyantomaftuh/AsyncDisplayKit,zeitgeist7/AsyncDisplayKit,JetZou/AsyncDisplayKit,chrisdanford/AsyncDisplayKit,yufenglv/AsyncDisplayKit,grgcombs/AsyncDisplayKit,lappp9/AsyncDisplayKit,skullacy/AsyncDisplayKit,romyilano/AsyncDisplayKit,xujim/AsyncDisplayKit,DanielAsher/AsyncDisplayKit,donpark/AsyncDisplayKit,supriyantomaftuh/AsyncDisplayKit,zeyang101909/AsyncDisplayKit,RuiAAPeres/AsyncDisplayKit,frankenthumbs/AsyncDisplayKit,zhangyabinzyb/AsyncDisplayKit,nivanchikov/AsyncDisplayKit,bimawa/AsyncDisplayKit,zhangyabinzyb/AsyncDisplayKit,donpark/AsyncDisplayKit,nrcmedia/AsyncDisplayKit,k1ok3n/AsyncDisplayKit,kesiking/AsyncDisplayKit,levi/AsyncDisplayKit,benzguo/AsyncDisplayKit,levi/AsyncDisplayKit,jellenbogen/AsyncDisplayKit,sabby3861/AsyncDisplayKit,maicki/AsyncDisplayKit,tharhtet/AsyncDisplayKit,NghiaTranUIT/AsyncDisplayKit,gazreese/AsyncDisplayKit,sabby3861/AsyncDisplayKit,DanielAsher/AsyncDisplayKit,DanielAsher/AsyncDisplayKit,xujim/AsyncDisplayKit,eanagel/AsyncDisplayKit,dskatz22/AsyncDisplayKit,facebook/AsyncDisplayKit,yufenglv/AsyncDisplayKit,adamdahan/AsyncDisplayKit,programming086/AsyncDisplayKit,frankenthumbs/AsyncDisplayKit,aaronschubert0/AsyncDisplayKit,gazreese/AsyncDisplayKit,sabby3861/AsyncDisplayKit,maicki/AsyncDisplayKit,KacheFlowe/AsyncDisplayKit,supriyantomaftuh/AsyncDisplayKit,harryworld/AsyncDisplayKit,smyrgl/AsyncDisplayKit,TheoJL/AsyncDisplayKit,paulyoung/AsyncDisplayKit,mtxs007/AsyncDisplayKit,zeitgeist7/AsyncDisplayKit,hejunbinlan/AsyncDisplayKit,steveram/AsyncDisplayKit,garrettmoon/AsyncDisplayKit,200895045/AsyncDisplayKit,zeitgeist7/AsyncDisplayKit,zdw19840929/AsyncDisplayKit,dskatz22/AsyncDisplayKit,TheoJL/AsyncDisplayKit,levi/AsyncDisplayKit,eanagel/AsyncDisplayKit,zeyang101909/AsyncDisplayKit,frankenthumbs/AsyncDisplayKit,paulyoung/AsyncDisplayKit,hannahmbanana/AsyncDisplayKit,george-gw/AsyncDisplayKit,maicki/AsyncDisplayKit,programming086/AsyncDisplayKit,tomizimobile/AsyncDisplayKit,todotodoo/AsyncDisplayKit,treejames/AsyncDisplayKit,yangyangluoluo/AsyncDisplayKit,rcancro/AsyncDisplayKit,michaelvillar/AsyncDisplayKit,yufenglv/AsyncDisplayKit,nivanchikov/AsyncDisplayKit,jellenbogen/AsyncDisplayKit,msdgwzhy6/AsyncDisplayKit,bimawa/AsyncDisplayKit,marmelroy/AsyncDisplayKit,tomizimobile/AsyncDisplayKit,zdw19840929/AsyncDisplayKit,Adlai-Holler/AsyncDisplayKit,tharhtet/AsyncDisplayKit,KacheFlowe/AsyncDisplayKit,paulyoung/AsyncDisplayKit,wangjiangwen/AsyncDisplayKit,smyrgl/AsyncDisplayKit,eeeyes/AsyncDisplayKit,owenwuef/AsyncDisplayKit,todotodoo/AsyncDisplayKit,harryworld/AsyncDisplayKit,ERussel/AsyncDisplayKit,rmls/AsyncDisplayKit,200895045/AsyncDisplayKit,NghiaTranUIT/AsyncDisplayKit,chrisdanford/AsyncDisplayKit,ppamorim/AsyncDisplayKit,KacheFlowe/AsyncDisplayKit,PodsMakleso6/AsyncDisplayKit,zdw19840929/AsyncDisplayKit,Teino1978-Corp/Teino1978-Corp-AsyncDisplayKit,JetZou/AsyncDisplayKit,garrettmoon/AsyncDisplayKit,hbucius/AsyncDisplayKit,lappp9/AsyncDisplayKit,garrettmoon/AsyncDisplayKit,hbucius/AsyncDisplayKit,msdgwzhy6/AsyncDisplayKit,rahul-malik/AsyncDisplayKit,DanielAsher/AsyncDisplayKit,angi2/AsyncDisplayKit,xujim/AsyncDisplayKit,rcancro/AsyncDisplayKit,RuiAAPeres/AsyncDisplayKit,marmelroy/AsyncDisplayKit,paulyoung/AsyncDisplayKit,adamdahan/AsyncDisplayKit,hannahmbanana/AsyncDisplayKit,dvan001/AsyncDisplayKit,owenwuef/AsyncDisplayKit,200895045/AsyncDisplayKit,levi/AsyncDisplayKit,codepython/AsyncDisplayKit,21451061/AsyncDisplayKit,TheoJL/AsyncDisplayKit,meitianapp/AsyncDisplayKit,JetZou/AsyncDisplayKit,JetZou/AsyncDisplayKit,eeeyes/AsyncDisplayKit,samhsiung/AsyncDisplayKit,Xinchi/AsyncDisplayKit,programming086/AsyncDisplayKit,aaronschubert0/AsyncDisplayKit,rmls/AsyncDisplayKit,21451061/AsyncDisplayKit,adamdahan/AsyncDisplayKit,grgcombs/AsyncDisplayKit,hejunbinlan/AsyncDisplayKit,nivanchikov/AsyncDisplayKit,jellenbogen/AsyncDisplayKit,eeeyes/AsyncDisplayKit,jellenbogen/AsyncDisplayKit,treejames/AsyncDisplayKit,marmelroy/AsyncDisplayKit,michaelvillar/AsyncDisplayKit,sabby3861/AsyncDisplayKit,meitianapp/AsyncDisplayKit,21451061/AsyncDisplayKit,programming086/AsyncDisplayKit,todotodoo/AsyncDisplayKit,chrisdanford/AsyncDisplayKit,rmls/AsyncDisplayKit,hannahmbanana/AsyncDisplayKit,steveram/AsyncDisplayKit,rmls/AsyncDisplayKit,Xinchi/AsyncDisplayKit,Xinchi/AsyncDisplayKit,garrettmoon/AsyncDisplayKit,msdgwzhy6/AsyncDisplayKit,PodsMakleso6/AsyncDisplayKit,flovouin/AsyncDisplayKit,codepython/AsyncDisplayKit,harryworld/AsyncDisplayKit,eeeyes/AsyncDisplayKit,michaelvillar/AsyncDisplayKit,marmelroy/AsyncDisplayKit,treejames/AsyncDisplayKit,smyrgl/AsyncDisplayKit,aaronschubert0/AsyncDisplayKit,k1ok3n/AsyncDisplayKit,flovouin/AsyncDisplayKit,Adlai-Holler/AsyncDisplayKit,pytouzain/AsyncDisplayKit,yufenglv/AsyncDisplayKit,jflinter/AsyncDisplayKit,RuiAAPeres/AsyncDisplayKit,frankenthumbs/AsyncDisplayKit,tomizimobile/AsyncDisplayKit,michaelvillar/AsyncDisplayKit,programming086/AsyncDisplayKit,treejames/AsyncDisplayKit,tomizimobile/AsyncDisplayKit,dvan001/AsyncDisplayKit,NghiaTranUIT/AsyncDisplayKit,owenwuef/AsyncDisplayKit,pytouzain/AsyncDisplayKit,Cen92/AsyncDisplayKit,yangyangluoluo/AsyncDisplayKit,dskatz22/AsyncDisplayKit,pytouzain/AsyncDisplayKit,mtxs007/AsyncDisplayKit,angi2/AsyncDisplayKit,Cen92/AsyncDisplayKit,benzguo/AsyncDisplayKit,zeitgeist7/AsyncDisplayKit,KacheFlowe/AsyncDisplayKit,bimawa/AsyncDisplayKit,NghiaTranUIT/AsyncDisplayKit,grgcombs/AsyncDisplayKit,msdgwzhy6/AsyncDisplayKit,donpark/AsyncDisplayKit,RuiAAPeres/AsyncDisplayKit,dskatz22/AsyncDisplayKit,mtxs007/AsyncDisplayKit,lappp9/AsyncDisplayKit,dvan001/AsyncDisplayKit,Adlai-Holler/AsyncDisplayKit,nrcmedia/AsyncDisplayKit,kesiking/AsyncDisplayKit,george-gw/AsyncDisplayKit,tomizimobile/AsyncDisplayKit,eanagel/AsyncDisplayKit,codepython/AsyncDisplayKit,rcancro/AsyncDisplayKit,Teino1978-Corp/Teino1978-Corp-AsyncDisplayKit,rahul-malik/AsyncDisplayKit,wangjiangwen/AsyncDisplayKit,rcancro/AsyncDisplayKit,skullacy/AsyncDisplayKit,dskatz22/AsyncDisplayKit,KacheFlowe/AsyncDisplayKit,george-gw/AsyncDisplayKit,frankenthumbs/AsyncDisplayKit,aaronschubert0/AsyncDisplayKit,samhsiung/AsyncDisplayKit,chrisdanford/AsyncDisplayKit,pytouzain/AsyncDisplayKit,nrcmedia/AsyncDisplayKit,jflinter/AsyncDisplayKit,Teino1978-Corp/Teino1978-Corp-AsyncDisplayKit,TheoJL/AsyncDisplayKit