client.c stacking.c: fixing looping transient case for group transient windows. now a window which is transient for a group is *not* transient for any other transient windows in the group (perviously the other window had to be transient for the group to be excluded, now it can be transient for anything).
client.c/h event.c render.c/h: adjustnig icon handling a bit. will be converting the legacy pixmap icons into rgba data so they can be handled the same as netwm icons.