CBLT-42:  add windows builds to sync_gateway master

Change-Id: I5421af46894fd9949f50886c1c482ea54ec8f0a6
Reviewed-on: http://review.couchbase.org/37195
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>