Useful for everybody wanting to package godot.
Fixes#1026.
-> Retain the old behaviour: path in error msg only when exporting.
-> User templates override system templates
-ItemList control for easier lists/thumbnails
-New file dialog, with support for thumbnails, favorites, recent places,
etc
-Moved .fscache out of the project, no more bugs due to committed/pulled
.fscache!
-Dir dialog now sorts directories
