[xmonad] Wayland

Wasn't there a GSoC project to add Wayland support? In case you wonder why I'm considering it: Wayland is becoming a serious alternative, especially to solve tearing on newer Intel GPUs. Older Intel GPUs do not tear under Xorg at all, but newer ones tear constantly if you don't force vsync via compton.

From what I gather, this is a solved issue under Wayland.