Cleanup of CSS for Grid

[BryanForbes]

Currently, when you include Grid.css and tundraGrid.css and sort a column you get two sorting arrows. This stems from overlapping styles. We should be able to include both Grid.css and tundraGrid.css much like dijit.css and tundra.css. This also needs to work for both the old and new grids.

[toonetown]

(In [14579]) Refs #7180 - first step of cleanup - remove duplicated information from the theme css files. Also updated the test files to import both the theme and the core files, if needed.

[toonetown]

(In [14589]) Refs #7180 - rename css class names to not have dashes, so that there will not be conflicts with compat grids - and to also better match naming conventions of dijit. The only one that has the same class name is dojoxGrid - and there is no difference between the compat styling and the normal styling of that node !strict

[toonetown]

Also see revision [14588] -

To test the compatibility layer of this fix, I dropped in the tests directory from 1.1 and verified that they all worked correctly.