Merge pull request #9 from pawelmiszcz/master

Add parameter broadcast_address
Move default value for broadcast_address into cassandra::params

Apart from being consistent with the other configuration parameters it also
enables overriding the broadcast_address setting with a global variable
$cassandra_broadcast_address.
Update README.md
Update Puppet versions in Travis CI build config
Update Modulefile for releasing version 0.4.0
Fix typo in README.md
Add Ruby 2.0.0 to Travis CI test matrix