Syntax: Replace slots/signals by Q_SLOTS/Q_SIGNALS
EditorController: Clean commented code
Action: Add generic actions

Size/Scale Changed
Move Dx/Dy
AssemblyCommand: Use more pertinent action enum value for command Id
ButtonBar: Set spin editable, and send adequate signals when edited
ButtonBarController: Add completing of the new signal from button bar
EditorController: Handle new signal from button bar
TreeViewController: Move role enum to a separate file
TreeViewController: Re-factoring of last item selected handling
CompositorWidget: Rename CompositorController variable
CompositorController: Add signal on assembly open status
TreeViewController: Add open status in assembly node

Set node in italic when assembly is closed
TreeViewController: Add open status in ItemSelected
TreeViewController: Set some slots as private

An move them in the cpp file to match order in hpp
TreeViewController: Move element node on lower/raise event
ButtonBar: Fix button naming
ProjectSortFilterModel: Create a sort proxy model

Sort only the first level (assembly name) by alphabetic order
Keep the second level sort by row index
TreeViewController: Set action for interaction with opened assemblies

Action:
- choose background
- remove background
- select element
- remove element
AssemblyAction: Connect actions from TreeView to the EditorController
Fixup TreeViewController: Set action for interaction