1) press the heart while the game is running
2) select a scene to live edit from the opened scenes
3) edit/add/remove nodes or resources, change their properties, etc.
4) watch changes reflected in running game, in all places this scene is
edited
5) It's not perfect obviously, but the aim of it is to try to reflect
your changes as best as possible in the running game.
-ability to edit multiple scenes at the same time
-resource internal IDs are now persistent, this makes multiple scene
editing possible but maaaaay result in file corruption bugs (tested and
could not find anything but possibility exists because core code
changed, report immediately if you find this).
-properly save settings, layout, etc when edited
-script editing is independent from scene editing now
-show a yellow box when a script belongs to the scene
