Toolbars Port preparation (GTK4)

• The Toolbar base class will now derive from Gtk::Box instead of Gtk::Toolbar.
• Added custom ToolbarMenuButton widget to take care of overflow handling in the toolbars on resizing.
  • Derives from Gtk::MenuButton.
  • It is also configurable with the get_derived_widget() method and thus can be added to the Glade file with ease.
  • To add a toolbar widget into a popup, just add the "tag" of the ToolbarMenuButton as a style class to the widget to be moved.
  • In future, one can use the priority property to determine which ToolbarMenuBUtton should be collapsed or expanded first.
• Added the ability to move any number of children in the toolbar into popups if the window is narrow.
  • A toolbar can have multiple popups
  • Each popup can have any number of children

Tools ported:

• Select
• Node
• Shape (Boolean)
• Rect*
• Arc*
• Star*
• Box3D*
• Spiral*
• Pen*
• Pencil
• Calligraphy
• Text
• Gradient*
• Mesh*
• Dropper*
• Paint Bucket*
• Tweak
• Spray
• Eraser
• Connector*
• LPE*
• Measure
• Zoom*
• Pages*
• Marker
• Commands

• Uncollapsed toolbar narrower than collapsed Select toolbar.