SQS Transport for #48

I added support for SQS as a transport (supporting IAM Roles, provided credentials, and multiple regions).  It adds boto 2.8 as a requirement.  https://github.com/josegonzalez/beaver/issues/48

I also noticed that the base transport object was getting the logger as a parameter, but never setting it on self.  Not sure if that was intentional or not (none of the other transports did any logging, so I wasn't sure).