Allow Float column width percentage and float column pixel width

Pixel width of columns was parsed to Int, eg 2.35% became 0.02 not 0.0235. The resulting pixelWidth was also floored to int, 60.6 became 60 resulting in whitespace in my grid.
Merge pull request #582 from WimAtIHomer/patch-1

Allow Float column width percentage and float column pixel width