Setting column default width
Not setting the width was causing all the columns to disappear
on screens with low real estate.
Merge pull request #85 from freemanirl/set-default-width

Setting column default width
Adding internal column concept

Adding the ability to have internal columns, columns that are never
rendered in the grid and are not selectable in the column chooser.
These columns are only for internal use of the grid.
Merge pull request #87 from mrkrstphr/internal-columns

Adding internal column concept
Fix issues with grid column spacing when multiselect was used
Merge pull request #88 from fuzzysignal/fix-grid-col-spacing

Fix issues with grid column spacing when multiselect was used