make background movement in pixel instead of % to be more consistent
make background movement in pixel instead of % to be more consistent

jianxiansining/skrollr,mumer92/skrollr,mtgrunt/skrollr,AlphaStaxLLC/skrollr,GerHobbelt/skrollr,danieldietrich/skrollr,lauffenp/skrollr,dshreyas11/skrollr,Kalmani/skrollr,SanhNX/skrollr,kavallo/skrollr,matthewgoodwin/skrollr,dommuthu/skrollr,mikesoops/skrollr,boregan/skrollr,bspiritxp/skrollr,10by10pixel/skrollr,MassImpact/skrollr,fengyiyi/skrollr,Prinzhorn/skrollr,fxck/skrollr,RohithKP/skrollr,VladimirGavrilov/skrollr,divisionparzero/skrollr,unxsist/skrollr,cwj10/skrollr,piyushkhemka/skrollr,xiamiLi/skrollr,liqk2014/skrollr,garylgh/skrollr,unxsist/skrollr,leonardykris/skrollr,Bilyachenko/skrollr,2947721120/skrollr,Bilyachenko/skrollr,BenHeubl/skrollr,liqk2014/skrollr,AlphaStaxLLC/skrollr,utkarshx/skrollr,garylgh/skrollr,winglua/skrollr,kavallo/skrollr,mtgrunt/skrollr,2947721120/skrollr,bspiritxp/skrollr,udhayam/skrollr,leendx/skrollr,GerHobbelt/skrollr,RohithKP/skrollr,winglua/skrollr,jianxiansining/skrollr,mumer92/skrollr,mikesoops/skrollr,lauffenp/skrollr,VladimirGavrilov/skrollr,grigorkh/skrollr,triplecanopy/skrollr,npmcomponent/pinkTurtle-skrollr,dszls/skrollr,fxck/skrollr,jeff235255/skrollr,thenaughtychild/skrollr,fengyiyi/skrollr,Kalmani/skrollr,antoniocicerone/skrollr,dszls/skrollr,SanhNX/skrollr,10by10pixel/skrollr,dshreyas11/skrollr,piyushkhemka/skrollr,Prinzhorn/skrollr,dommuthu/skrollr,divisionparzero/skrollr,cwj10/skrollr,boregan/skrollr,BenHeubl/skrollr,danieldietrich/skrollr,antoniocicerone/skrollr,leendx/skrollr,thenaughtychild/skrollr,MassImpact/skrollr,utkarshx/skrollr,alvarotrigo/skrollr,jeff235255/skrollr,alvarotrigo/skrollr,grigorkh/skrollr,matthewgoodwin/skrollr,xiamiLi/skrollr,udhayam/skrollr,NancyFan/skrollr,leonardykris/skrollr,NancyFan/skrollr