rename utils to pbutils

rename utils to pbutils

Original commit message from CVS:
* configure.ac:
* docs/libs/gst-plugins-base-libs-docs.sgml:
* docs/libs/gst-plugins-base-libs-sections.txt:
* gst-libs/gst/Makefile.am:
* gst-libs/gst/interfaces/mixer.c:
* gst-libs/gst/pbutils/Makefile.am:
* gst-libs/gst/pbutils/descriptions.c:
(gst_pb_utils_get_source_description),
(gst_pb_utils_get_sink_description),
(gst_pb_utils_get_decoder_description),
(gst_pb_utils_get_encoder_description),
(gst_pb_utils_get_element_description),
(gst_pb_utils_add_codec_description_to_tag_list),
(gst_pb_utils_get_codec_description), (gst_pb_utils_list_all):
* gst-libs/gst/pbutils/descriptions.h:
* gst-libs/gst/pbutils/install-plugins.c:
* gst-libs/gst/pbutils/install-plugins.h:
* gst-libs/gst/pbutils/missing-plugins.c:
(gst_missing_uri_source_message_new),
(gst_missing_uri_sink_message_new),
(gst_missing_element_message_new),
(gst_missing_decoder_message_new),
(gst_missing_encoder_message_new),
(gst_missing_plugin_message_get_description):
* gst-libs/gst/pbutils/missing-plugins.h:
* gst-libs/gst/pbutils/pbutils.c: (gst_pb_utils_init):
* gst-libs/gst/pbutils/pbutils.h:
* gst-libs/gst/utils/Makefile.am:
* gst-libs/gst/utils/base-utils.c:
* gst-libs/gst/utils/base-utils.h:
* gst-libs/gst/utils/descriptions.c:
* gst-libs/gst/utils/descriptions.h:
* gst-libs/gst/utils/install-plugins.c:
* gst-libs/gst/utils/install-plugins.h:
* gst-libs/gst/utils/missing-plugins.c:
* gst-libs/gst/utils/missing-plugins.h:
* gst-plugins-base.spec.in:
* gst/playback/Makefile.am:
* gst/playback/gstdecodebin.c:
* gst/playback/gstdecodebin2.c:
* gst/playback/gstplaybasebin.c: (setup_subtitle),
(gen_source_element):
* gst/playback/gstplaybin.c: (plugin_init):
* tests/check/Makefile.am:
* tests/check/libs/pbutils.c: (GST_START_TEST),
(test_pb_utils_install_plugins_do_callout), (libgstpbutils_suite):
* tests/check/libs/utils.c:
rename utils to pbutils