Add Linux support for both wayland and x11

[xedrac]

Thank you for creating the wonderful Graphite keyboard layout!

I spent some time making this easy to install on Linux, and figured I'd contribute it back upstream so other people could benefit from it.

I'd like to do the same thing for Windows, just in case I ever have the misfortune of having to use it from time to time.

Let me know if you have any questions or concerns. Thanks!