session manager: set_event_loop() to our event loop
session manager: set_event_loop() to our event loop

This will enable widgets to do things using our event loop if they want.

Closes #1046

Signed-off-by: Tycho Andersen <6b523322678240882acbb4da5312a12d8cd0082d@tycho.ws>

tych0/qtile,qtile/qtile,ramnes/qtile,tych0/qtile,ramnes/qtile,qtile/qtile