JSCBC-766: Added support for GeoPolygon search queries.
JSCBC-766: Added support for GeoPolygon search queries.

Motivation
----------
The search query team has introduced support for performing
polygon based geo queries against an FTS index.  The SDKs
should pick up support for this.

Changes
-------
Added a new search class for specifying a Geo Polygon query.

Change-Id: Ibd59ae541f8571e500f902f680fdbb8d1d84ae66
Reviewed-on: http://review.couchbase.org/c/couchnode/+/136092
Reviewed-by: David Kelly <d83cd2a93a916ce0b0d4c1349b44be044799feca@gmail.com>
Tested-by: Brett Lawson <c8c4369773d7d7226e031f0c4af62e3f38a08510@gmail.com>

brett19/couchnode,couchbase/couchnode,couchbase/couchnode,couchbase/couchnode,couchbase/couchnode,brett19/couchnode,brett19/couchnode