initial checkin for coordinator

Change-Id: I51ba2d4ba27a1799b95f2e573874491b9b1f9bdc
Reviewed-on: http://review.couchbase.org/41453
Reviewed-by: Deepkaran Salooja <deepkaran.couchbase@gmail.com>
Reviewed-by: John Liang <johliang00@gmail.com>
Tested-by: John Liang <johliang00@gmail.com>