+ Fix boolean operation panel
More choices in Sketcher grid and later switching to um
Draft: Small bugfix in dxf importer - fixes #1317
Arch: added a couple of useful properties to Site object
Arch: small bugfix to ifc exporter
+ Support to write out mesh name
Part: Changes to dimension

    move 2 icons to main gui
    enable and disable stepped buttons
    move reset dialog to control widget
    only dimension 1 linear solution
Arch: Frame object - fixes #1166, #1314
Raytracing: Added aspect ratio to POV output - fixes #1315
improves airfoil-import
little bugfix, closes polyline again