Added warning for scrollView property and some comments
Added warning for scrollView property and some comments

jianwoo/GMGridView,gank0326/GMGirdView,BlessNeo/GMGridView,loverly/GMGridView,gmoledina/GMGridView,D-cocoa/GMGridView,ashfurrow/GMGridView,liulinjian/GMGridView,SuPair/GMGridView,d191562687/GMGridView,Sensis/GMGridView,matej/GMGridView,gelosie/GMGridView,111minutes/GMGridView-CSFork,PocketScientists/GMGridView,fhchina/GMGridView