Reorganize as subproject of jetty-nosql-kvs

hi

I found your fork of `jetty-nosql-memcached` with interesting changes :)  Though, I found the  redundant copy of `jetty-nosql-kvs` project.

I reorganize essential part (Couchbase!) of your fork of `jetty-nosql-memcached` as `jetty-nosql-couchbase`. This makes to be able to share changes for `jetty-nosql-kvs` between memched and Couchbase impls. I hope you'll send me some fixes for `jetty-nosql-kvs` :)

Regards