Add Riak Control test.

This test produces *failing* cases for Riak Control against to cut 1.4.1
release, but passes when run against a tentative master-based 1.4.2
build.

This test currently covers:

* Rolling upgrade of all nodes, while every node runs control.
* Verifies nodes do not fail during the rolling upgrade.
* Verifies two releases back.
* Verifies that 1.3+ resources return properly and deserialize.
* Verifies that 1.2+ resources return properly and deserialize.
* Intermediate and final state verification of the response JSON from
  Riak Control.
* Verify convergence of capability.

This test does not cover:

* Riak 1.2 node ping, stats, and fallback resources, which are not used
  by the user interface.
* Parsing the Riak 1.2 response to ensure values return the correct
  state.