make it more obvious that title is WM_NAME
group spawn arg, starts the client in that group

it uses net_wm_pid so the client should implement it, but most does

Closes #442
Fix screen mirroring while respecting ordering

Closes #439
widget/wlan.py:

Fix for IOError when wlan device is deactivated (Softswitch)

Closes #438
Fix a test

apparently int objects aren't marshallable, so we have to return a string here.