Added n1ql client for queryport.

- implements datastore.Index{} interface.
- Export functions to,
    Load2iIndexes()
    Create2iPrimaryIndex()
    Create2iIndex()

Change-Id: I0ebd26beffca9416ae86d0a89b04d5178a9f4f32
Reviewed-on: http://review.couchbase.org/43753
Reviewed-by: Sriram Melkote <siri@couchbase.com>
Reviewed-by: Pratap Chakravarthy <prataprc@couchbase.com>
Tested-by: Pratap Chakravarthy <prataprc@couchbase.com>