Removal of moxi resulted in removal of vbuckettool - a nice command line utility

It would be nice to add it back under kv_engine/programs. Quite a number of people are used to typing the following to check where their document lives:

curl -X GET -u Administrator:password http://localhost:8091/pools/default/buckets/{bucket-name} | /opt/couchbase/bin/tools/vbuckettool - {key}