Adding send_batch to Queue

This release adds Queue.send_batch, as well as adds extra error checking, and automatic conversion of message body into either raw text or attributes.

Various cleanup, fixing the job.elapsed

This makes Job.elapsed work with the AWS metadata instead of using our own.

Initial Release

This is the first release of qoo, which contains some of the essential functionality stripped out of my internal helper modules for sqs. It also contains the beginning of the test suite.