add EWMH compliance statement
faster window type checks
full support for Above, Below, Desk and Dock

 - full support for _NET_WM_STATE_ABOVE, _NET_WM_ACTION_ABOVE
 - full support for _NET_WM_STATE_BELOW, _NET_WM_ACTION_BELOW
 - full support for _NET_WM_WINDOW_TYPE_DOCK
 - full support for _NET_WM_WINDOW_TYPE_DESKTOP