Add support for geometries

The spatial views now also store the supplied geometry and return it
on query time. When a view is created without a geometry, it won't
be included in the result.

Change-Id: Idb7418bb5aff124d0ecf9dfb03445c28a2b36381
Reviewed-on: http://review.couchbase.org/40370
Reviewed-by: Sarath Lakshman <sarath@couchbase.com>
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Volker Mische <volker.mische@gmail.com>