message: Updated the README sample for use of bundler options.
diff: @@ -122,13 +122,18 @@ mergeStream(project.sources(), project.dependencies())
  The bundler() method accepts an options object to configure bundling. See [Using polymer-bundler programmatically](https://github.com/polymer/polymer-bundler#using-polymer-bundler-programmatically) for a detailed list of accepted options.
  ```js
  +const {generateCountingSharedBundleUrlMapper,
  + generateSharedDepsMergeStrategy} = require('polymer-bundler');
  +
  +mergeStream(project.sources(), project.dependencies())
  .pipe(project.bundler({
  excludes: ['bower_components/polymer-code-mirror'],
  sourcemaps: true,
  stripComments: true,
  - strategy: require('polymer-bundler/lib/bundle-manifest')
  - .generateSharedDepsMergeStrategy(3)
  + strategy: generateSharedDepsMergeStrategy(3),
  + urlMapper: generateCountingSharedBundleUrlMapper('shared/bundle_')
  }))
  + .pipe(gulp.dest('build/'));
  ```
  ### Generating a Service Worker
  