Add support for authentication to cassandra seeds.
Add support for specififying and connecting to a local datacenter within both the CassandraJournal and CassandraSnapshotStore.
Merge pull request #12 from mediacrossinginc/cassandra-datacenter-aware

Cassandra authentication and datacenter aware
Upgrade to Akka 2.3.4
Merge branch 'master' into r-0.3
Set release version to 0.3.2