check/Makefile.am: clean up environment for when registry gets built versus when actual tests are run; valgrind seems...

Original commit message from CVS:

* check/Makefile.am:
clean up environment for when registry gets built versus
when actual tests are run; valgrind seems to not report
leaks if GST_PLUGIN_PATH is set to some specific values
* check/gst/gstbin.c: (GST_START_TEST):
add more refcounting checks; maybe this exposes a
preroll lock bug ?
* common/check.mak:
* gst/base/gstbasesink.c: (gst_base_sink_handle_object):
* gst/check/gstcheck.h:
* gst/gstbin.c: (bin_element_is_semi_sink), (gst_bin_get_state),
(gst_bin_change_state):
* gst/gstpad.c: (gst_pad_activate_push), (gst_pad_chain):
add/fix debugging/whitespace