make default group comparer function more robust - see pull request: fix sort order in Chrome #1019
make default group comparer function more robust - see pull request: fix sort order in Chrome #1019

yamass/SlickGrid,RobertoMalatesta/SlickGrid,jesenko/SlickGrid,gbark/SlickGrid,cheminfo/SlickGrid,manju-reddys/SlickGrid,yamass/SlickGrid,RobertoMalatesta/SlickGrid,6pac/SlickGrid,cheminfo/SlickGrid,cheminfo/SlickGrid,iCoreSolutions/SlickGrid,manju-reddys/SlickGrid,iCoreSolutions/SlickGrid,jesenko/SlickGrid,6pac/SlickGrid