Deleted the wrong character when changing to american spelling.

mitterlib/network/__init__.py

@@ -263,7 +263,7 @@ class Networks(object):
         self._save()
         return
 
-    def favouite(self, message):
+    def favorite(self, message):
         """Change the favorite status of the message. Returns the new
         favorite status."""
         assert(isinstance(message, NetworkData))