make_model: add data() method for synchrorized data fetching

src/util/make_model.js

@@ -49,6 +49,7 @@ export default (options={}) => {
 		// reflection methods
 		configs() { return _configs },
 		cache() { return _cache },
+		data(offset=0, limit=Infinity) { return _cache.data && _cache.data.slice(offset, offset+limit) || [] },
 
 		// main methods
 		select(offset=0, limit=Infinity) {