The other subfolders of tools/ had already been moved to either
editor/, misc/ or thirdparty/, so the hiding the editor code that
deep was no longer meaningful.
(Manual redo of 49c065d29c)
-Rearrange favorites in fs dock with drag and drop
-Removed import -> sub-scene, moved to scenetree contextual menu
-Removed import -> re-import , moved and integrated to FS dock
-Added ability in FS dock to re-import more than one resource
simultaneously
-Added ability to drag from native filesystem explorer to Godot, only
works on Windows though
-Removed scene reimport merge options, never worked well. Eventually
merging materials should be re-added
-Added ability to set custom root node type when importing scenes
-Re-Import is now automatic, can be configured back to manual in editor
settings
-Added resource previews in property list for many resource types
