Map Display Improvement

I improved the map display routine as I evaluated some flags and several maps look much better now.
The map editor is also rearranged to make the handling more clear and intuitive.

The Mu maps had some problems with the lowest level, but not anymore:

The order of the two map layers is a problem which still remains. I haven't found the information yet that tells me which map arrangement data corresponds to which map layer. As a result some maps still don't look as they are supposed to (only house interior maps). As an example, Neil's Cottage:

If i flip the order of the map layers everything looks fine. But I need to find that information in the ROM first...