A simpler kafka consumer

```
kafka = KafkaConsumer('topic1')
for m in kafka:
    print m

kafka = KafkaConsumer('topic1', 'topic2',
                      group_id='my_consumer_group',
                      auto_commit_enable=True,
                      auto_commit_interval_ms=30 * 1000,
                      auto_offset_reset='smallest')

for m in kafka:
    process_message(m)
    kafka.task_done(m)
```
not sure I understand this -- in normal case you would do

m = kafka.next() # adds offset to deque
kafka.task_done(m) # removes offset from deque
kafka.commit() # ? nothing on the deque...  what to commit?