Squashed commit of the following:

commit 7a581316282bde9b0c8b7b94abbde2bd30ae3755
Author: Alex Rogers <arogers@voltdb.com>
Date:   Fri Nov 21 15:44:43 2014 -0500

    Change confusing receiver/replica/agent terminology in DR to producer/consumer

commit 8ae64b8c51e0f3cba76440f15304e94ac45df28f
Author: Alex Rogers <arogers@voltdb.com>
Date:   Wed Nov 19 12:02:07 2014 -0500

    Annotate DR control responses with request type

commit f7fc5fb3b4c234bef6ec6b73d19d9196cb74d949
Author: Alex Rogers <arogers@voltdb.com>
Date:   Wed Nov 12 12:07:15 2014 -0500

    Initial commit of refactored AgentReceiver