Add alternative method for developing using watch and start-dist

Because of this issue https://github.com/electron/electron-compile/issues/146

package.json

@@ -6,6 +6,8 @@
   "scripts": {
     "start": "electron src",
     "build": "rm -rf dist && babel src -d dist --copy-files && ln -s ../node_modules dist/ && ln -s ../package.json ./dist/",
+    "watch": "npm run build && babel src -d dist --copy-files -w",
+    "start-dist": "./node_modules/electron-prebuilt-compile/node_modules/electron/cli.js dist",
     "package": "electron-packager dist LosslessCut --out=package --asar --overwrite --all --version 1.3.8",
     "lint": "eslint ."
   },