riak_test for proxy_get + EE 1.4

https://github.com/basho/riak_repl/pull/228
https://github.com/basho/riak_ee/pull/127
https://github.com/basho/riak_cs/pull/516

This test can take ~30 minutes to run. 
cc @seancribbs - once merged, this will need the GiddyUp treatment