Clustering fixes
Various fixes made durng Cassandra 1.2 testing
Enable I-CSCF/S-CSCF function by default
Reverse I/S-CSCF ports
Updates to security groups
Updates to security groups with correct port
Merge pull request #91 from Metaswitch/icscf_test

[Reviewer: Rob] Icscf test
Fix issue with Cassandra running out of entropy
Harmonize Memcached and Cassandra clustering logic
Merge branch 'master' into cass1.2