Bump lavu minor and add an APIChanges entry for audioconvert functions.

doc/APIchanges

@@ -13,6 +13,10 @@ libavutil:     2011-04-18
 
 API changes, most recent first:
 
+2012-xx-xx - xxxxxxx - lavu 51.32.0 - audioconvert.h
+  Add av_get_channel_layout_channel_index(), av_get_channel_name()
+  and av_channel_layout_extract_channel().
+
 2012-05-25 - e0e0793 - lavu 51.31.0 - opt.h
   Add av_opt_set_bin()
 

libavutil/avutil.h

@@ -152,7 +152,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR 51
-#define LIBAVUTIL_VERSION_MINOR 31
+#define LIBAVUTIL_VERSION_MINOR 32
 #define LIBAVUTIL_VERSION_MICRO  0
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \