TS-938 - Don't merge

Adding the config and a gen_server to handle the c* nodes. But this uses elysium 0.1.7 so the files changed are really misleading.

Also the query seems to work, but it is not currently being used.
For one, the gen_server defaults to a 5 second timeout. The other reason is that you won't be able to query the current state of the gen_server to see if update is running, or even worse, you won't be able to get the node list on demand. The problem with using the Elysium_LB_Queue to find out nodes is that some may be checked out. This gen_server should always be responsive to a request for 'get_cassandra_nodes'.