Client wrapper for complete & partial updates

Change-Id: I862baeae86cd7e36707f27cc9c68b9b1f17360ad
Reviewed-on: http://review.couchbase.org/26432
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>