allowing values of zero to be evaluated by the sort function
Built js on windows box
Merge branch 'allow_sorting_of_zeros' of git://github.com/kdstew/ng-grid into kdstew-allow_sorting_of_zeros

Conflicts:
	build/ng-grid.debug.js
	ng-grid-1.6.0.debug.js
Merge branch 'kdstew-allow_sorting_of_zeros'

Conflicts:
	src/services/SortService.js