v0.3: Script interface

This release implements ScriptInterface, so that auto-completion is possible in other scripts using @export var. This is documented here.

The C++ container is also updated to build in parallel, greatly reducing compilation times. Remember to docker pull!

Thanks to @Ughuuu for the idea and implementation.

Full Changelog: https://github.com/libriscv/godot-sandbox/compare/v0.2...