Update print statements to print() functions

docs/usage/streaming_api.rst

@@ -27,10 +27,10 @@ Now set up how you want to handle the signals.
     class MyStreamer(TwythonStreamer):
         def on_success(self, data):
             if 'text' in data:
-                print data['text'].encode('utf-8')
+                print(data['text'])
 
         def on_error(self, status_code, data):
-            print status_code
+            print(status_code)
 
             # Want to stop trying to get data because of the error?
             # Uncomment the next line!