A general speedup should be apparent, with even more peformance increase when compiling optimized.
WARNING: Tested and it seems to work, but if something breaks, please report.
-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.
