fix invalid base64 encoding, #16
golang convert []byte to base64 in JSON automatically
Add PutRecords functionality

AWS Kinesis has released a batch PUT API for bulk additions to a stream.

* Add PutRecords functionality to Kinesis library

https://github.com/sendgridlabs/go-kinesis/issues/15
replace reader
merge
Extract WaitForStream function

The wait code from the example app is quite helpful. This give users of
the library an opportunity to leverage it without duplication.

* Add short-circuit on CreateStream if it already exists
* Extract WaitForStream function