* configure.ac: gstreamermm requires newest version of glibmm module,
      because of improvements in generate_wrap_init.pl script.
    * gst-plugins-bad/gstreamermm-plugins-bad/wrap_init.h: use Gst::Bad
      namespace for wrap_init function.
    * gst-plugins-bad/src/Makefile.am: use Gst::Bad namespace as a global
      namespace in plugins-bad module.
    * gst-plugins-bad/src/glbasefilter.hg:
    * gst-plugins-bad/src/glfilter.hg: remove _GMMPROC_EXTRA_NAMESPACE
      macro (it's not necessary anymore).