Original commit message from CVS:

* gst/gst.defs:
parse_launch also owns the return ref
* gst/gstbin.override:
fix a leak in get_by_name()
* testsuite/common.py:
loop when garbage collecting; necessary when deleting, say,
a pipeline, that contains elements, to ensure the elements
also get collected
* testsuite/test_element.py:
* testsuite/test_pipeline.py:
test for garbage collection