Update of Dropwizard Extra for newer Kafka, dropwizard, and asynchbase

[csconnell]

I made a few simple modifications to the project, which include:

• Updating the JavaDoc so it would all process properly. There were some non-compliant javadoc statements that would not process if you built the javadoc through Maven
• Upgraded dropwizard to 0.9.1.
• Upgraded the Kafka version from 0.8.1.1 to 0.8.2.2
• Removed the Kafka7 module from the overall POM and build (easy to add back, if needed)
• Upgraded asynchbase from 1.4.1 to 1.7.0 and made some changes in the health checks to reflect the hbase upgrade (.META and .ROOT don't exist any longer in newer versions of hbase)

Initially these changes were not going to be part of a pull request, but I had requests to see if we could get some of these into the main project ... as such I didn't break them into different branch / commit sets because performing these upgrades were viewed as a single "upgrade" operation.