Add standalone program to operate on buckets

As part of project Tynset we need to be able to test lots of
buckets isolated with memcached (without having to run the
entire cluster) to monitor the internal resource usage. This
program may be used to create/delete/list buckets.

Change-Id: Iac39a648f7596a937bcac0e0f9d93cd25b97dad4
Reviewed-on: http://review.couchbase.org/42740
Reviewed-by: Dave Rigby <daver@couchbase.com>
Tested-by: buildbot <build@couchbase.com>