waylandloginmanager: keep WAYLAND_HOST and WAYLAND_GUEST for wl backed sessions

git-svn-id: https://rebeccablackos.svn.sourceforge.net/svnroot/rebeccablackos@3178 56e3d1a8-0179-4092-b3e2-9fbbcda0c0a9
configureseats: Send SIGUSR1 and SIGUSR2, instead of switching TTYs. This removes the need for the flicker, to get the devices to apply. if WAYLAND_HOST is set, it will send the signals to that server, (in the case of a nested session). Otherwise it will send the signals to the WAYLAND_DISPLAY

git-svn-id: https://rebeccablackos.svn.sourceforge.net/svnroot/rebeccablackos@3179 56e3d1a8-0179-4092-b3e2-9fbbcda0c0a9