Add _wm_class to Icon in Systray
Add _wm_class to Icon in Systray

87ac116 added this attribute to the X11 window classes, for use in the
`info()` command to report the wm_class of windows. This was left off
the `Icon` class in systray.py, leading to AttributeErrors when there
are icons.

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