System.config({
  baseURL: "/",
  defaultJSExtensions: true,
  transpiler: false,
  paths: {
    "twitter": "//platform.twitter.com/widgets.js"  // must be a path, map will cause an error when bundling (May change in SystemJS Builder v0.15)
  },

  meta: {
    "twitter": {
      "build": false,      // don't build (May not be needed in SystemJS Builder v.15)
      "scriptLoad": true,  // load in a script tag to avoid XHR error (option, SystemJS assumes script load when format: 'global')
      "format": "global",
      "exports": "twttr"
    }
  }
});