1. Use Command Key = Super Left key
2. Grab Command shortcuts via `xcb_grab_key`
3. Track active window via EWMH extension
4. Track active window's class via ICCCM extension
5. On Command shortcut choose appropriate native shortcut
   based on the active window's class and send native
   shortcut via XTEST extension

Everything is hardcoded for now and only translation of
Command+C/V to Control+C/V for regular programs, and
Control+Shift+C/V for termite (terminal emulator) is supported.