message: adding watch script
diff: "release:minor": "npm version minor && npm publish",
  "release:major": "npm version major && npm publish",
  "compile": "rm -rf lib/ && node_modules/.bin/babel -d lib/ src/",
  + "watch": "babel --watch -d lib/ src/",
  "jshint": "jshint src/. test/. --config",
  "mocha": "mocha test/ --compilers js:babel-core/register",
  "test": "npm run compile && npm run jshint && npm run mocha"
  