mention module flag in readme
mention module flag in readme

dashersw/sweet.js,lukehoban/sweet.js,sweet-js/sweet-core,lukehoban/sweet.js,sweet-js/sweet.js,sweet-js/sweet.js,mozilla/sweet.js,renyaoxiang/sweet.js,getshuvo/sweet.js,renyaoxiang/sweet.js,dashersw/sweet.js,getshuvo/sweet.js,mozilla/sweet.js