Add some default implementations and documentation.
Add some default implementations and documentation.

fortime/pykafka,aeroevan/pykafka,fortime/pykafka,yungchin/pykafka,appsoma/pykafka,jofusa/pykafka,tempbottle/pykafka,sontek/pykafka,wikimedia/operations-debs-python-pykafka,wikimedia/operations-debs-python-pykafka,sammerry/pykafka,vortec/pykafka,vortec/pykafka,sontek/pykafka,yungchin/pykafka,thedrow/samsa,wikimedia/operations-debs-python-pykafka,benauthor/pykafka,tempbottle/pykafka,thedrow/samsa,aeroevan/pykafka,thedrow/samsa,benauthor/pykafka,jofusa/pykafka,appsoma/pykafka,benauthor/pykafka,sammerry/pykafka