Kinesis CLI

Let me know what you think re:https://github.com/sendgridlabs/go-kinesis/issues/4 -- of course I'm happy to keep this out of the repo if you don't think it belongs, but I've found it a useful way to use the api while doing kinesis development, and it might serve as a more complete batch of example code as well?

Note: this relies on https://github.com/sendgridlabs/go-kinesis/pull/5, so that one should be merged first.