Add automated acceptance tests

[mpareja]

We'll need some automated acceptance tests to really rest assured that uncorded's clustering is working as expected - especially for ELB auto-discovery and replication. A few highlevel acceptance tests I would love to see:

• given an ASG with 2 instances running uncorded
  • add a document to a node
    • the doc is available to the other nodes
    • the doc is available after restarting a node
    • add another instance of uncorded to the ASG
      • the previously added doc is available on the new instance
  • remove a document from a node
    • the removed document is removed from all nodes