a whole lotta work!!

- refactoring
- completely changed the tooling (adding elements)
- better re-use for more stable editing
- new elements
- ui adjustments
- LINT for stair-editing
- many more changes

mapview/model/MMFloorStair.h

@@ -5,7 +5,7 @@
 #include "IHasParams.h"
 #include "MMFloorOutlinePolygon.h"
 
-#include "../elements/MV2DElementStair.h"
+#include "../2D/MV2DElementStair.h"
 #include "../3D/MV3DElementStair.h"