OpenMW CS: Minor region map fixes and improvements
This MR fixes two bugs:
- Column width is rectangular not square, atleast with latest QT libs when building locally. 0.48 binaries are fine. Either a regression or something changed in QT perhaps.
- Unable to drag region from table into region map, this bug is also present in 0.48.0 binaries
And introduces a feature:
- Show different brush for land vs water - this makes creating region maps from scratch so much easier and can help region modders see where landmass is without loading cells