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".
Key, touch and joystick events will be passed directly from the UI thread to Godot, so they can benefit from agile input flushing.
As another consequence of this new way of passing events, less Java object are created at runtime (`Runnable`), which is good since the garbage collector needs to run less.
`AndroidInputHandler` is introduced to have a smaller cross-thread surface. `main_loop_request_go_back()` is removed in favor just inline calling `send_window_event()` at the most caller's convenience (i.e., leveraging the new `p_deferred`` parameter as appropriate).
Lastly, `get_mouse_position()` and `get_mouse_button_state()` now just call through `Input` to avoid the need of sync of mouse data tracked on the UI thread.
