Adding horizontalScrolling property and overriding of jqgrid widths.
Allow the grid widths to be calculated from the titles or be set to a fixed width
Adding unit tests
Changes to allow buttons to be used as menu items.
Ensure that internal scrolling works when horizontal scrolling is also applied.
Updating docs.
Merge pull request #219 from PrimeRevenue/feature/grid_horizontal_scroll

Feature/grid horizontal scroll