Set the name of the logger to twilio

Proper python logging for a module.

Twilio is currently logging to the root log handler. If I set my application to debug mode, I might not want to see your logs. So therefore with this change you can do:

     logging.getLogger("twilio").setLevel(logging.ERROR) 

in your main application so that you can suppress twilio to only error messages.

https://docs.python.org/2/library/logging.html