es_out: add es index per type to meta information.

Per ES type (AUDIO_ES, VIDEO_ES, SPU_ES) is used by interfaces (like: qt4 for menu items). However from the meta data this order cannot be related to any select video, audio or spu because this information is not present in the meta data. By adding this meta data item as Index one can find out which meta data information is related to the selected audio, video, spu track as presented by interfaces.

src/input/es_out.c

@@ -2641,6 +2641,9 @@ static void EsOutUpdateInfo( es_out_t *out, es_out_id_t *es, const es_format_t *
     if( psz_type )
         input_Control( p_input, INPUT_ADD_INFO, psz_cat, _("Type"), psz_type );
 
+    input_Control( p_input, INPUT_ADD_INFO, psz_cat, _("Index"),
+                        "%d", es->i_channel + 1 );
+
     if( es->i_meta_id != es->i_id )
         input_Control( p_input, INPUT_ADD_INFO, psz_cat, _("Original ID"),
                        "%d", es->i_id );