Implemented precise key events

[EliteMasterEric]

This feature PR adds two new key press event, one for pressing a key and one for releasing a key. The distinction is that the precise key press events include the SDL timestamp of the keypress. By calling SDL_GetTicks() (which this PR also includes an interface for), you can calculate the number of milliseconds since the key was pressed. This is useful for mitigating input latency.

Notes:

• The previous PR (#1561) is now deprecated and has been closed.
• This PR creates a new, otherwise-redundant key press event to prevent breaking changes from modifying the existing key press event.
• The event has been made to be compatible with both Native and HTML5.
• The timestamp provided by the keypress event is only suitable for comparision, and is not an absolute/Unix timestamp.
  • This behavior probably needs to change somehow, for example making a Timestamp object with various compare functions available.
  • On native, compare to lime._internal.backend.native.NativeCFFI.lime_sdl_get_ticks().
  • On HTML5, compare to js.Browser.window.performance.now().
• The old key press event can be deprecated and eventually removed in a future update.
• Once #1684 is tested, debugged, and implemented, the event can be updated to use nanosecond timings instead.

[EliteMasterEric]

Since I made this PR I also had to tweak these code changes to make a similar addition to gamepads.

That commit is public.

[EliteMasterEric]

Redone in #1802 to include the gamepad stuff and exclude extra commits.