Make maven run cassandra on random port to prevent conflicts

Use the build-helper-maven-plugin to find random unused ports and
reserve them for use by cassandra. Set system properties via the
integration test runner to tell BF what port it can find cassandra on.
Do not start cassandra runner by default

We do not need maven to start cassandra for all modules (ex- the root
parent project, blueflood-elasticsearch, etc). So skip the cassandra
runner by default, and selectively turn it on in the projects that
need it.
add groupId for build-helper-maven-plugin
Merge pull request #137 from dlobue/dynamic_allocate_cass_ports

Dynamic allocate cass ports
Merge branch 'master' into statsd_integration
statsd module needs cassandra.