Allow grids autoheight setting
Allow grids scrollbarpage setting
Allow grids scrollbarwidth setting
Fixes compiler hint about unused variable
Improve horizontal srcollbar behaviour
Add optional scrollbar styles
Fix ColMax() calculation.

When resizing the grid at runtime, the old implementation sometimes
called ColumnWidth[] with a -1 index causing an AV error.
Merge branch 'feature/jml-grids' into develop