V1.1.0 updates

Some long needed updates. Improves usability and leverages more of the datapoints available through the airbrake error reporting API. Includes a helper for fetching a logger object, pre-configured with an AirbrakeHandler, and many other improvements.

Updated [the README](https://github.com/samstav/airbrake-python/blob/v1.1.0/README.md) to reflect the simplified interface.
(duplicating one of my responses....)

Should the exception be thrown as soon as you try to instantiate the Handler (which I think would be valid, since the url cannot even be built). I think some would argue that it should be lazy, and wait to throw an Exception once the first attempt to call notify() is made.