offsetTop cross-browser compatibility fix
offsetTop cross-browser compatibility fix

Just changed the offsetTop function to prevent unexpected results in different browsers.
jgknott/angular-inview,Nex9/angular-inview,talis/angular-inview,mastertheblaster/angular-inview,MartyIX/angular-inview,eugenehp/angular-inview,talis/angular-inview,Nex9/angular-inview,thenikso/angular-inview