Another round of lastgenre logging nitpicks

- Printing out album/item in default format could lead to unreadable
  clutter depending on the user's configured formats.
- The album's name and the individual tracks' title should be just
  sufficient to provide context as well readability.
- Log like this while importing as well as in standalone runs.

beetsplug/lastgenre/__init__.py

@@ -419,7 +419,8 @@ def lastgenre_func(lib, opts, args):
                 for album in lib.albums(ui.decargs(args)):
                     album.genre, src = self._get_genre(album)
                     self._log.info(
-                        "genre for album {0} ({1}): {0.genre}", album, src
+                        'genre for album "{0.album}" ({1}): {0.genre}',
+                        album, src
                     )
                     if "track" in self.sources:
                         album.store(inherit=False)
@@ -433,9 +434,8 @@ def lastgenre_func(lib, opts, args):
                             item.genre, src = self._get_genre(item)
                             item.store()
                             self._log.info(
-                                "genre for track {0} ({1}): {0.genre}",
-                                item,
-                                src,
+                                'genre for track "{0.title}" ({1}): {0.genre}',
+                                item, src,
                             )
 
                         if write:
@@ -459,7 +459,8 @@ def imported(self, session, task):
             album = task.album
             album.genre, src = self._get_genre(album)
             self._log.debug(
-                "added last.fm album genre ({0}): {1}", src, album.genre
+                'genre for album "{0.album}" ({1}): {0.genre}',
+                album, src
             )
 
             # If we're using track-level sources, store the album genre only,
@@ -469,7 +470,8 @@ def imported(self, session, task):
                 for item in album.items():
                     item.genre, src = self._get_genre(item)
                     self._log.debug(
-                        "added last.fm item genre ({0}): {1}", src, item.genre
+                        'genre for track "{0.title}" ({1}): {0.genre}',
+                        item, src,
                     )
                     item.store()
             # Store the album genre and inherit to tracks.