implemented libspotify seek

mopidy/backends/libspotify/__init__.py

@@ -122,7 +122,11 @@ class LibspotifyPlaybackController(BasePlaybackController):
         return self._set_output_state('PLAYING')
 
     def _seek(self, time_position):
-        pass # TODO
+        self._set_output_state('READY')
+        seek_to_ms = int(time_position) * 1000
+        result = self.backend.spotify.session.seek(seek_to_ms)
+        self._set_output_state('PLAYING')
+        return True
 
     def _stop(self):
         result = self._set_output_state('READY')

mopidy/frontends/mpd/protocol/playback.py

@@ -293,7 +293,7 @@ def seek(frontend, songpos, seconds):
         Seeks to the position ``TIME`` (in seconds) of entry ``SONGPOS`` in
         the playlist.
     """
-    raise MpdNotImplemented # TODO
+    return frontend.backend.playback._seek(seconds)
 
 @handle_pattern(r'^seekid "(?P<cpid>\d+)" "(?P<seconds>\d+)"$')
 def seekid(frontend, cpid, seconds):