Update ng-grid to v2.0.8

The source files come from https://github.com/angular-ui/ng-grid/tree/2.0.8/build.
Currently, the 2.0.8 build is not advertised, but does exist as a branch in their build.  The latest advertised version is 2.0.7 and they suggest users no longer contribute to 2.x builds and instead focus on the new 3.x branch.