PCBC-172: Add design document examples

Change-Id: I6cd13136a9de326cd2e3bfa6d054b2d9508243c0
Reviewed-on: http://review.couchbase.org/25436
Tested-by: Trond Norbye <trond.norbye@gmail.com>
Reviewed-by: Michael Nitschinger <michael.nitschinger@couchbase.com>