added revrpc package and example

Change-Id: I3423489f97ddb3ec157d40a0fd9e41d52f494e81
Reviewed-on: http://review.couchbase.org/44066
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>