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.
I don't really care for it either.  The problem is that we can set a height value, but not a min or max height and there fore it will end up negating the auto expansion.  I am open for discussion on how to better handle the min height of grid rows.