Export additional function for the spatial views

In anticipation for the spatial views, export some additional functions.

Change-Id: Ide2df7ada829e5ad1212da2b8ba50fcbaf03814a
Reviewed-on: http://review.couchbase.org/40115
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Nimish Gupta <nimish@couchbase.com>