Improve tool settings

[TokisanGames]

Fixes #89
Fixes #300
Fixes #329

Changes to the tool settings bar:

• Sub menus popup on hover (see Brush, Advanced)
• Color picker hides on mouse_exit
• add_settings now passes a dictionary w/ variable parameters
  • new parameter: label, which overwrites the name
  • new flag: NO_LABEL which hides the label
  • new flag: ADD_SEPARATOR which adds a vertical separator before the setting
• Labels are separated from controls and are clickable buttons that reset settings to defaults, or toggle checkboxes

Renamed files:

• editor/editor.gd -> /editor.gd
• editor/components -> /src
• editor/brushes -> /brushes
• point_picker -> multi_picker

Misc fixes:

• Fixes picking color/height/roughness outside of regions resulting in Color(nan) and invalid values
• Automatic regions ignored for non-sculpting brushes
• Changing collisions layers changes in realtime instead of on generation