Minor bug fixes

* When you initiate a producer with a non-existant queue, the queue is
  created. However this partition info is not reflected in <tt>KafkaClient()</tt>
  immediately. So, we wait for a second and try loading it again.

  Without this fix, if we do <tt>producer.send_messages()</tt> after creating a new
  queue, the library will throw a <tt>StopIteration</tt> exception.

* In <tt>SimpleConsumer()</tt>, the defaults are not as mentioned in the comments.
  Fix this (or do we change the documentation?)