Remove mp3info function & remove list_do_action from plugin_api

Change-Id: Ia9a2d6889679832f23b19a989927277ba886cba4

docs/API

@@ -197,14 +197,6 @@ Memory allocation
      each and returns a pointer to the allocated memory. The memory is set to
      zero.
 
-ID3
-
-  #include <id3.h>
-  bool mp3info(mp3entry *entry, char *filename);
-
-     Return FALSE if successful. The given mp3entry is then filled in with
-     whatever id3 info it could find about the given file.
-
 Various
 
   #include <kernel.h>

docs/PLUGIN_API

@@ -1324,13 +1324,6 @@ time_t mktime(struct tm *t)
     \return
     \description
 
-bool mp3info(struct mp3entry *entry, const char *filename)
-    \group misc
-    \param entry
-    \param filename
-    \return FALSE if successfull
-    \description The given =entry= is filled in with whatever id3 info it could find about the given =filename=
-
 void mutex_init(struct mutex *m)
     \group kernel/ system
     \param m