Replace GST_PLUGINS_LIBS_* with GST_PLUGINS_BASE_*

Replace GST_PLUGINS_LIBS_* with GST_PLUGINS_BASE_*

Original commit message from CVS:
2005-07-01  Jan Schmidt  <thaytan@mad.scientist.com>
* ext/libcaca/Makefile.am:
* ext/mad/Makefile.am:
* gst/effectv/Makefile.am:
* gst/udp/Makefile.am:
Replace GST_PLUGINS_LIBS_* with GST_PLUGINS_BASE_*

* ext/mad/gstid3tag.c: (gst_id3_tag_src_query),
(gst_id3_tag_src_event), (gst_id3_tag_sink_event),
(gst_id3_tag_chain), (plugin_init):
* ext/mad/gstmad.c: (gst_mad_src_query), (gst_mad_chain):
Signedness warning fix, use gst_pad_get_peer instead of GST_PAD_PEER
in querying and event handling, because we're not holding the pad
lock and the peer may disappear.
* gst/avi/gstavidemux.c: (gst_avi_demux_parse_subindex),
(gst_avi_demux_parse_index), (gst_avi_demux_massage_index):
Signedness warning fixes.

* gst/videofilter/gstvideotemplate.c: (plugin_init):
Remove gst_library_load