adding mixer docs

Original commit message from CVS:
adding mixer docs

configure.ac

@@ -928,10 +928,10 @@ m4/Makefile
 )
 AC_OUTPUT
 
-echo -n "configure: *** Plug-ins that will be built :"
+echo -n "configure: *** Plug-ins that will be built:"
 echo -e "$GST_PLUGINS_YES" | sort
 echo
-echo -n "configure: *** Plug-ins that will not be built :"
+echo -n "configure: *** Plug-ins that will not be built:"
 echo -e "$GST_PLUGINS_NO" | sort
 echo
 if test "x$BUILD_EXTERNAL" = "xno"; then

gst-libs/gst/interfaces/mixeroptions.c

@@ -91,7 +91,7 @@ gst_mixer_options_init (GstMixerOptions * mixer_options)
 
 /**
  * gst_mixer_options_get_values:
- * @mixer_optnios: The #GstMixerOptions item that owns the values.
+ * @mixer_options: The #GstMixerOptions item that owns the values.
  *
  * Get the values for the mixer option.
  *