- Sometimes `StackFrame.GetMethod()` returns null (e.g.: latest frame of a `MissingMethodException`). Still not sure what to do with that frame (maybe skip it), but at least it no longer fails.
- Skip `CSharpLanguage::debug_get_current_stack_info()` if an error is printed from `GDMonoUtils::update_corlib_cache()`.
- Fix crash when calling `GDMonoUtils::print_unhandled_exception(exc)` if there is no ScriptDebugger attached.
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.
- Allow non-public fields to be exported as well (to avoid confusion).
- Set PROPERTY_HINT_RESOURCE_TYPE for resource derived fields.
- Support enums and automatically fill PROPERTY_HINT_ENUM's hint_string for enum fields.
