CBLT-42:  now creating Sync Gateway windows executable, in a zip file

Change-Id: I8a67ef60922eae5391eb82980b2000cb35852ac5
Reviewed-on: http://review.couchbase.org/33940
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>