* Update the "public" offset before yielding the message
* Add an option to SimpleConsumer.commit that excludes the current
  offset

Ref #26

consumer.py and conn.py will be done later after pending merges

* When you initiate a producer with a non-existant queue, the queue is
  created. However this partition info is not reflected in KafkaClient()
  immediately. So, we wait for a second and try loading it again.

  Without this fix, if we do producer.send_messages() after creating a new
  queue, the library will throw a StopIteration exception.

* In SimpleConsumer(), the defaults are not as mentioned in the comments.
  Fix this (or do we change the documentation?)

* There was a problem with the way the consumer iterator worked.
  for eg: assume that there were 10 messages in the queue/topic
  and you iterate over it as -

  for msg in consumer:
       print (msg)

  At the end of this, 'offset' that is saved is 10.
  So, if you run the above loop again, the last message (10) is repeated.

  This can be fixed by adjusting the offset counter before fetching
  the message

* Avoid some code repeat in consumer.commit()

* Fix a bug in send_offset_commit_request() invocation in consumer.py

* Fix missing imports

Conflicts:
	kafka/consumer.py

Removed get_messages API, added test for get_pending

Auto commit timer is not periodic

The auto commit timer is one-shot. After the first commit, it does
not fire again. This ticket fixes the issue.

Also, in util.ReentrantTimer(), some duplicate code was cleaned up