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".
* API kept the same (Although functions could be renamed to set_metadata/get_metadata in a later PR), so not much should change.
* Metadata now exposed as individual properties.
* Properties are editable in inspector (unless metadata name begins with _) under the metadata/ namespace.
* Added the ability to Add/Remove metadata properties to the inspector.
This is a functionality that was requested very often, that makes metadata work a bit more similar to custom properties in Blender.
