rabbitpy.base improvements and bug fixes
rabbitpy.base improvements and bug fixes

- Rename AMQPChannel._close AMQPChannel.close
- Use the AMQPChannel.rpc method on Close to encapsulate waiting for a CloseOk
- Don't use Queue.get due to CPU issues and refactor around that issue

gmr/rabbitpy,gmr/rabbitpy,jonahbull/rabbitpy