* Disable or delete some menu items, which are inappropriate for cut objects
* For cut objects added menu item "Invalidate cut info" to disconnect related cut parts of initial object
* If just one part is kept after cut performance, than don't apply a cut info for this object.
+ CutGizmo: Fixed selection of the mode
An object has connectors -> Connectors mode
An object doesn't has connectors -> CutPlane mode
* CutGizmo: Fixed a label scale
* Fixed deselection of selected connectors, when moving the camera
* Implemented update of the settings for selected connectors
* Connector selection: Ctrl shortcut is changed to Shift to compatibility of the selection/deselection with rectangle selection
* ObjectList & Selection: Show Connectors in the Scene, when CutConnectors Item is selected
* ObjectList: refactoring: extract the adding of volumes to the add_volumes_to_object_in_list()
* If some connector is selected on 3dScene -> select all connectors of this object
* GLGizmoScale3D : check if grabber is enabled, when do rendering
+ GLGizmoCut: refactoring : split render_cut_plane_grabbers to several functions
1) Nodes allocated using std::deque, not as std::set of pointers for
less memory allocator pressure.
2) Parents changed to parent indices, so that one may allocate side
by side data for nodes addressed by these indices. Thus now elemens
are being marked as deleted and the whole node database is being
compacted in one shot instead of deleting an element from std::set.
3) Removed SUPPORT_TREE_ONLY_GRACIOUS_TO_MODEL for simplicity, it was
never used.
4) Fixed crash when slicing multiple objects with three supports.
Reworked the Archimedean Chords, Hilbert and Octagram Spiral infill
generators to
1) Generate solid infill as not aligned with other solid infill layers.
This may surprise some users as the pattern over multiple islands
will be different, maybe not that nice. This may change in the future.
2) Sparse infill is always aligned and generated over the whole object,
however newly the generated lines are trimmed with a snug bounding box
while being generated.
3) For Archimedean chords the accuracy was not applied correctly, leading
to higher accuracy for dense infill and lower accuracy for sparse infill.
