+ fixes #0001873: Error working with getSelectionEx()[0].SubObjects
+ improve whitespace, fix warnings
+ fixes #0001838: When In Sketcher Make It Difficult To Mistakenly Delete A Feature
+ improve whitespace
+ fix minor issue in toggle construction command
+ revert changes for issue 1873
+ fixes #0000711: fileted borders not projected on 2D drawing + deleted views still showing
+ make undo/redo accessible from drawing view
+ fixes #0000976: Usability: default Material drop-down is not the active material type
+ fix conversion from Qi image to Inventor when image uses a color table
+ fixes #0000957: Sketch view problem when go to edit
+ do not long apply changes in mesh settings on existing mesh objects
+ fixes #0001060: Editing sketch crashes FreeCAD
+ fixes #0001720: Freecad crash when handling invalid sketches
+ fixes #0001878: model refine exception
+ fixes #0001877: associate a grayed out icon with Freecad's backup files (fcstd1)
+ fixes #0001616: crash when selecting 'Edit Sketch'
Fix duplicate 'optimized' when using new libpack

When using a CLbundler libpack, PYTHON_LIBRARY has both optimized and debug
libs, but it doesn't when using an old libpack, which was the reason for
commit f5a4e680
+ fix constraint evaluation function
+ fixes #0001876: replace helpful text in task tab with an info button