Update cassandra-env.sh template to latest version from Cassandra 1.2
Change gem source to https://rubygems.org
Update cassandra.yaml template to version from Cassandra 1.2

* Added additional parameters which are now available in the Cassandra configuration:
  ** start_native_transport
  ** start_rpc
  ** native_transport_port
  ** num_tokens
  ** internode_compression
  ** disk_failure_policy
* Default Partitioner is now org.apache.cassandra.dht.Murmur3Partitioner
* Added notice if initial_token is set. num_tokens (see vnodes) should be used now
* Added repository information for RedHat