This commit adds new functionality to NativeScript, namely:
- ability to set and get documentation for classes, methods,
signals and properties
- ability to set names and type information to method arguments
- ability to set and get type tags for nativescripts
- ability to register instance binding data management functions
- ability to use instance binding data
Using `misc/scripts/fix_headers.py` on all Godot files.
Some missing header guards were added, and the header inclusion order
was fixed in the Bullet module.
