-Detect when free() might crash the project and throw error
-fixed 2D Bounce in physics (3d still broken)
-renamed “on_top” property to “behind_parent”, which makes more sense, old on_top remains there for compatibility but is invisible.
-large amount of fixes
-made GUI Theme editor usable
-editor does not allow to export or create .pck in the same path as a project
-changed .pck format (lacked support for versioning so couldn't change it), previous was causing crashes and is now incompatible, just re-export.
-will not look for .pck files recursively, was causing unexpected behaviors
-fixed execution of Godot in paths with non unicode characters in Windows, OSX and Linux.