Copying go-couchbase and gomemcached dependency.

To prevent 2i requirements and changes affecting sibling projects.

Change-Id: Ib0c671866dd5127cefcd52dadb003648dc8e8952
Reviewed-on: http://review.couchbase.org/43613
Reviewed-by: Sriram Melkote <siri@couchbase.com>
Reviewed-by: Pratap Chakravarthy <prataprc@couchbase.com>
Tested-by: Pratap Chakravarthy <prataprc@couchbase.com>