Formatted Leu

Fixed a little bug in Leu regarding number format. If no number format was selected the output format was one char too long, resulting in very ugly rounding errors. Already long time before I started to implement a solution to set the number format for a cell. But it was very crude and not ready to release, so I deactivated it for Leu 0.07. But this bug got me back to work. 😉 I started to implement a format settings window, a little bit inspired by the LibreOffice one. Finally its working, not perfect but already usable.

Also fixed some small problems with the color blending on selection for RTG systems (for <15bit screens it will just use a fixed color for the selection) and new now the fixed col/row will show where the selected cell is. much easier to find, especially if it is out of scroll area.