title: html-webpack-plugin doesn't inject css and meta tag into the generate file
body: <p>I run my vue app with webpack, which use webpack-simple template. My webpack setting is:</p>
  
  <pre><code>    entry: './src/main.js',
      output: {
          path: path.resolve(__dirname, './dist'),
          publicPath: '/dist/',  // 由于将index.html打包至dist下，生产环境设为'/'
          filename: 'build.js'
      },
      plugins: [new HtmlWebpackPlugin()]
  </code></pre>
  
  <p>originHtml:
  </p>
  
  <pre><code>&lt;html lang="en"&gt;
    &lt;head&gt;
      &lt;meta charset="utf-8"&gt;
      &lt;meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0"&gt;
      &lt;link rel="stylesheet" type="text/css" href="http://at.alicdn.com/t/font_9remcre60b3dte29.css"&gt;
      &lt;title&gt;earease&lt;/title&gt;
    &lt;/head&gt;
    &lt;body&gt;
      &lt;div id="app"&gt;&lt;/div&gt;
      &lt;script src="/dist/build.js"&gt;&lt;/script&gt;
    &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>generateHtml:</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
    &lt;head&gt;
      &lt;meta charset="UTF-8"&gt;
      &lt;title&gt;earEase&lt;/title&gt;
    &lt;/head&gt;
    &lt;body&gt;
    &lt;script type="text/javascript" src="/dist/build.js"&gt;&lt;/script&gt;&lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>Why the css and meta tag doesn't inject into the generated html file?</p>