Preserve event timestamps in X11 input driver

[192314]

Fix for #642 .

Analogous to this pull request:

The X11 XKeyEvent structure (and others) include a timestamp field, with 1ms resolution.
This was previously ignored causing the input timestamps to be set to the middle of each frame.
If the timestamps are passed through then the event timestamps are not coupled to the framerate and the polling issues are resolved.

[poco0317]

Looks fine. This doesn't concern me particularly, but I just want to point out that the commit listed isn't under your name.

Don't really have a way to test this other than confirming build is fine and having testers check it out.

[nico-abram]

Seems good to me too (Just from skimming it, no testing either)

Should crediting also be done in the commit message to the PR you linked in the message here?

[192314]

Should crediting also be done in the commit message to the PR you linked in the message here?

Sure, I just updated the commit message.