Add natefinch/npipe and twinj/uuid to Go dependencies

Change-Id: I1f1e1dbf68cd6746e7f5ca525f8f75b5a01201a2
Reviewed-on: http://review.couchbase.org/42920
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>