add apiversion setting

cloned from
https://github.com/lrusak/plugin.audio.subsonic/commit/761fc593c4a94027b
6483b98886a995b88bb03af

lib/libsonic_extra/__init__.py

@@ -33,7 +33,7 @@ class SubsonicClient(libsonic.Connection):
     - Add conventient `walk_*' methods to iterate over the API responses.
     """
 
-    def __init__(self, url, username, password):
+    def __init__(self, url, username, password, apiversion):
         """
         Construct a new SubsonicClient.
 
@@ -63,7 +63,7 @@ class SubsonicClient(libsonic.Connection):
 
         # Invoke original constructor
         super(SubsonicClient, self).__init__(
-            host, username, password, port=port)
+            host, username, password, port=port, apiVersion=apiversion)
 
     def getIndexes(self, *args, **kwargs):
         """