Add dumb benchmark example

Change-Id: I865276371693db09cd25f0c92789a9cd00070a20
Reviewed-on: http://review.couchbase.org/24262
Reviewed-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>