gst/gstbin.c (gst_bin_remove): Debugging fixes.

gst/gstbin.c (gst_bin_remove): Debugging fixes.

Original commit message from CVS:
2004-03-07  Andy Wingo  <wingo@pobox.com>

* gst/gstbin.c (gst_bin_remove): Debugging fixes.

* gst/schedulers/gstoptimalscheduler.c (destroy_group): Assert
there are no links to other groups when a group is destroyed.
(gst_opt_scheduler_pad_unlink): If the unlink means an element is
removed from a group, make sure the link count to elements linked
to other pads is appropriately decremented. This really fixes
#135672.

The 1.60->1.61 patch has been reapplied in light of this fix.

* gst/gstelement.c (gst_element_dispose): Really protect against
multiple invocations this time.