title: Delete or not create a file for each entry in webpack
body: <p>Hi I have a webpack config with these entry points:  </p>
  
  <pre><code>  entry: {
      'polyfills': './src/polyfills.ts',
      'vendor':    './src/vendor.ts',
      'app':       './src/app.ts',
      'css': './src/css/main.unique.scss',
      'index': './src/index.unique.html',
    },
  </code></pre>
  
  <p>My webpack is creating a <code>[name].bundle.js</code> and a <code>[name].map</code> for each entry.<br>
  It makes sense for the first 3 javascript entries but the CSS and the INDEX entries are just for processing my main CSS file and my main html file which get treated later by the <strong>ExtractTextPlugin</strong>  </p>
  
  <p>So after a build I'm stuck with some garbage like <code>css.bundle.js</code> and <code>css.map</code> which only contains:  </p>
  
  <pre><code>webpackJsonp([1],[
  /* 0 */
  /***/ function(module, exports) {
  
      // removed by extract-text-webpack-plugin
  
  /***/ }
  ]);
  //# sourceMappingURL=css.map
  </code></pre>
  
  <p>How can I tell webpack to <em>NOT</em> build files for some entries? (like css/index)<br>
  Or alternatively to delete those useless files after the compile?</p>
  
  <p>Thanks in advance</p>