* Draft: make move, rotate and scale commands link-aware
Fixes#12836.
Fixes#15681.
These changes are presented as a single ('big') PR because the mentioned commands have several similarities. Working on them seperately would have made less sense.
The commands have been made 'link-aware' meaning they can now handle Links and objects in linked containers.
This required several changes in the following main files. For each command all options are handled by a single function now (the `move`, `rotate` and `scale` functions). This was the only reasonable solution to correctly handle nested placements. As a result there is no longer a need to build very complex 'cmd' strings in the gui_*.py files (which is a good thing IMO).
Main files:
* move.py
* rotate.py
* scale.py
* gui_move.py
* gui_rotate.py
* gui_scale.py
* gui_trackers.py
The following files have also been updated:
* Draft.py: Imports updated.
* DraftGui.py: If `CopyMode` is changed the ghosts have to be updated. The move and rotate commands now also show previews of movable children. But since those are not copied they should be removed from the ghosts if `CopyMode` is changed to `True`.
* utils.py: Some helper functions have been added. An existing helper function (only used internally) has been renamed.
* gui_utils.py: The `select` function has been updated to accept a list of tuples to allow the reselection of nested objects.
* clone.py: A new property `ForceCompound`, necessary for non-uniform scaling, has been added.
* join.py: The `join_wires` function now returns the resultant wire objects.
* task_scale.py: Updated to allow negative scale factors. Support for `SubelementMode` preference added.
* dimension.py: `transform` methods added.
* layer.py: `get_layer` function added.
* svg.py: Updated to use `get_layer`.
* view_text.py: Instead of two added `coin.SoTransform()` nodes the main transform node is used instead. This was done so that ghosts of Draft Texts can be handled properly without requiring dedicated code in gui_trackers.py.
Notes:
* Support for "App::Annotation" is limited. Only their `Position` is handled (by the move and rotate commands).
* Support for "Image::ImagePlane" has been removed from the scale command. The object has its own calibrate feature (see https://wiki.freecad.org/Std_Import).
* Copies and clones are always created in the global space.
* Fix several unit test issues.
* Reset value that was changed while testing
* Rebase and update test_modification.py
* Reintroduce scaling of image planes
B-spline faces can be avoided if the absolute values of the scaling factors are the same. The `transformShape` method can handle this if two additional arguments are provided.
This includes `array`, `base`, `bezcurve`, `block`, `bspline`,
`circle`, `clone`, `dimension`, `draft_annotation`, `draftlink`,
`drawingview`, `ellipse`, `facebinder`, `fillet`, `label`,
`patharray`, `point`, `pointarray`, `polygon`, `rectangle`,
`shape2dview`, `shapestring`, `text`, `wire`, `wwproxy`.
These are added to the `draftobjects` Doxygen group
so that the functions and classes contained in each module
are listed appropriately in the automatically generated
documentation.
