Wrote prepublish in javascript

This allows storybook to be built in windows too.

package.json

@@ -12,7 +12,7 @@
     "mocha": "--require scripts/mocha_runner src/**/__tests__/**/*.js"
   },
   "scripts": {
-    "prepublish": "./scripts/prepublish.sh",
+    "prepublish": "node scripts/prepublish.js",
     "lint": "eslint src",
     "lintfix": "eslint src --fix",
     "testonly": "mocha $npm_package_options_mocha",

scripts/prepublish.js

@@ -0,0 +1,17 @@
+require('shelljs/global')
+var path = require('path')
+
+console.log("> Start transpiling ES2015")
+
+rm('-rf', 'dist')
+
+var babel = ['node_modules', '.bin', 'babel'].join(path.sep);
+exec(babel + " --ignore __tests__,manager --plugins transform-runtime src --out-dir dist")
+
+if(process.env.DEV_BUILD){
+  var webpack = ['node_modules', '.bin', 'webpack'].join(path.sep);
+  var webpackManagerConf = ["scripts", "webpack.manager.conf.js"].join(path.sep);
+  exec(webpack + " --config " + webpackManagerConf)
+}
+
+console.log("> Complete transpiling ES2015")