Suggester: take Album Artist

But it's not OK in dashboard ->
For example, search 'ayache' (for Superbus)
=> Result display 'Superbus' and we don't understand why

iTunesParser.py

@@ -147,7 +147,8 @@ class ITunesParser:
                 'Play Count': 0,
                 'Rating': 0,
                 'Genre': set(),
-                'Album': set()
+                'Album': set(),
+                'Album Artist': set()
                 }
 
         # Compute information
@@ -168,6 +169,9 @@ class ITunesParser:
         if 'Album' in track:
             self._artists[akey]['Album'].add(track['Album'])
 
+        if 'Album Artist' in track:
+            self._artists[akey]['Album Artist'].add(track['Artist'])
+
     def _process_album(self, track):
         """
             Process albums in the track part of library and return a JSON formated for a bulk ELS request