#28 Grid height/width setting - enhancements

[davout]

The current design for setting column and grid width and
height is too restrictive.

You should consider add the following new methods to
allow a more flexible approach...

setGridWidth(int aUnitsBasis, int aWidth)
setColumnWidth(int aColumn, int aUnitsBasis, int aWidth)
setGridHeight(int aUnitsBasis, int aHeight)
setRowHeight(int aRow, int aUnitsBasis, int aHeight).

Also your design only uses two of three available unit
basis types... pixels and percents. A third option exists -
'remainder' (e.g. width="*") which is quite useful for
making a designated colum,n grow or shrink according to
the available space, like