Add market argument to track info (#610)

spotipy/client.py

@@ -327,15 +327,16 @@ class Spotify(object):
         else:
             return None
 
-    def track(self, track_id):
+    def track(self, track_id, market=None):
         """ returns a single track given the track's ID, URI or URL
 
             Parameters:
                 - track_id - a spotify URI, URL or ID
+                - market - an ISO 3166-1 alpha-2 country code.
         """
 
         trid = self._get_id("track", track_id)
-        return self._get("tracks/" + trid)
+        return self._get("tracks/" + trid, market=market)
 
     def tracks(self, tracks, market=None):
         """ returns a list of tracks given a list of track IDs, URIs, or URLs