gst/gstbus.c (gst_bus_remove_signal_watch): New function, removes signal watches previously added via gst_bus_add_sig...

Original commit message from CVS:
2005-09-29  Andy Wingo  <wingo@pobox.com>

* gst/gstbus.c (gst_bus_remove_signal_watch): New function,
removes signal watches previously added via
gst_bus_add_signal_watch.
(gst_bus_add_signal_watch): Don't return the source id, just store
it on the bus if there wasn't an id already.

* gst/gstbus.h (GstBus): Add a couple new fields. API changes for
add_signal_watch and remove_signal_watch.