Add Wayland Backend.fake_click and Backend.get_all_windows methods
Add Wayland Backend.fake_click and Backend.get_all_windows methods

These work by eval-ing in the test Qtile instance. It might be nicer to
instead make these cmd_s on the `Core` if/when we expose cmd_ methods
from the Core.

qtile/qtile,ramnes/qtile,qtile/qtile,ramnes/qtile