Factor out systray Icon and Tray windows to use internal classes.
Factor out systray Icon and Tray windows to use internal classes.

This fixes a crashing bug when closing a window with a tray icon.

cortesi/qtile,de-vri-es/qtile,rxcomm/qtile,jdowner/qtile,farebord/qtile,jdowner/qtile,qtile/qtile,kopchik/qtile,flacjacket/qtile,xplv/qtile,kopchik/qtile,zordsdavini/qtile,tych0/qtile,flacjacket/qtile,kiniou/qtile,zordsdavini/qtile,apinsard/qtile,EndPointCorp/qtile,aniruddhkanojia/qtile,apinsard/qtile,nxnfufunezn/qtile,encukou/qtile,tych0/qtile,w1ndy/qtile,xplv/qtile,encukou/qtile,himaaaatti/qtile,dequis/qtile,kseistrup/qtile,andrewyoung1991/qtile,farebord/qtile,rxcomm/qtile,andrewyoung1991/qtile,soulchainer/qtile,de-vri-es/qtile,StephenBarnes/qtile,ramnes/qtile,kiniou/qtile,qtile/qtile,frostidaho/qtile,w1ndy/qtile,kynikos/qtile,EndPointCorp/qtile,himaaaatti/qtile,aniruddhkanojia/qtile,soulchainer/qtile,ramnes/qtile,StephenBarnes/qtile,nxnfufunezn/qtile,cortesi/qtile,frostidaho/qtile,kseistrup/qtile,kynikos/qtile,dequis/qtile