Feature/sqs event support

[kmbotts]

Greetings, I'm looking for some Python experience and this is something with which I'm pretty familiar. I wrote Java versions at my company and this is a very similar idea. SQS is probably the most commonly used event for us, so I took a crack at it. The SQSEventHandler will implement the perform method (now abstract) and iterate over all the SQS records calling its own "process_message" method for each record.

I also broke out all the classes into separate files, not sure if that's typical in Python programming, but was easier for me to navigate in the IDE.

Let me know what you think.