Fixing Resizing with Data-only columns.

The resize function was having issues when referencing columns that
were data only, and didn't have a corresponding DOM element.  So,
I limited the resize loop to the number of columns, and it's now checking
to see if the element exists.  I also cleaned up some code.
Merge pull request #89 from freemanirl/fix-stuff

Fixing Resizing with Data-only columns.
Add min-height to Griddly Bear Grids

Added workaround to Griddly Bear grids to for grid rows to have a
min-height.  Update the CSS and Javascript to reflect using a floated
div in order to provide rows with no data a minimum height.
Merge pull request #90 from thedeuceII/griddly-min-height

Add min-height to Griddly Bear Grids