STORM-303: Forward port of storm-kafka work.

This is a port of my work from
https://github.com/brndnmtthws/storm-kafka-0.8-plus to the current Storm
incubator project.

This is the code we use in our production cluster, which has been battle
tested with billions of messages per day.
Merge branch 'master' of github.com:brndnmtthws/incubator-storm
STORM-303: update changelog