Saving a TileMap node as scene, crashes the editor
Ubuntu 17.04- Godot version: 2.1.2/2.1.3
Issue description: Saving a TileMap node (on the tree) as a separate scene, crashes the editor after saving (sometimes do not save).
This only happens if the TileMap is the root of the new scene, if the TileMap is child of the node saved as scene, it works.
Steps to reproduce: Can be tested with demos (kinematic character, platformer). Select a TileMap and save it as a new scene.