Also start organizing editor-specific GUI components
into a dedicated folder, `editor/gui`.
Also move `editor_file_server` next to the rest of debugger classes.
* All core types masks are now correctly marked as bitfields.
* The enum hacks in MouseButtonMask and many other types are gone. This ensures that binders to other languages non C++ can actually implement type safe bitmasks.
* Most bitmask operations replaced by functions in BitField<>
* Key is still a problem because its enum and mask at the same time. While it kind of works in C++, this most likely can't be implemented safely in other languages and will have to be changed at some point. Mostly left as-is.
* Documentation and API dump updated to reflect bitfields in core types.
As many open source projects have started doing it, we're removing the
current year from the copyright notice, so that we don't need to bump
it every year.
It seems like only the first year of publication is technically
relevant for copyright notices, and even that seems to be something
that many companies stopped listing altogether (in a version controlled
codebase, the commits are a much better source of date of publication
than a hardcoded copyright statement).
We also now list Godot Engine contributors first as we're collectively
the current maintainers of the project, and we clarify that the
"exclusive" copyright of the co-founders covers the timespan before
opensourcing (their further contributions are included as part of Godot
Engine contributors).
Also fixed "cf." Frenchism - it's meant as "refer to / see".
Improvements:
* Occluder3D is now an abstract type inherited by: ArrayOccluder3D, QuadOccluder3D, BoxOccluder3D, SphereOccluder3D and PolygonOccluder3D. ArrayOccluder3D serves the same purpose as the old Occluder3D (triangle mesh occluder) while the rest are primitives that can be used to manually place simple occluders.
* Occluder baking can now apply simplification. The "bake_simplification_distance" property can be used to set a world-space distance as the desired maximum error, set to 0.1 by default.
* Occluders can now be generated on import. Using the "occ" and "occonly" keywords (similar to "col" and "colonly" for colliders) or by enabling on MeshInstance3Ds in the scene's import window.
Fixes:
* Fixed saving of occluder files after bake.
* Fixed a small error where occluders didn't correctly update in the rendering server.
Bonus content:
* Generalized "CollisionPolygon3DEditor" so it can also be used to edit Resources. Renamed it to "Polygon3DEditor" since it was already being used by other things, not just colliders.
* Fixed a small bug in "EditorPropertyArray" where a call to "remove" was left after the "remove_at" rename.
