title: Error: Expected 'styles' to be an array of strings
body: <p>I have been using <a href="https://github.com/qdouble/angular-webpack2-starter" rel="noreferrer">this seed project</a> to as the basis for my new Angular 2 project. Unfortunately, it does not come configured to use scss, so I have to add that configuration myself.</p>
  
  <p>I am using <a href="https://material.angular.io/" rel="noreferrer">Angular Material</a> so am importing a default theme in my app component like this:</p>
  
  <pre><code>@Component( {
      selector: 'my-app',
      styles: [require('./app.component.css'), require('./material2-app-theme.scss')],
      templateUrl: './app.component.html'
  } )
  </code></pre>
  
  <p>However, this yields the following error in the browser at runtime:</p>
  
  <pre><code>Uncaught Error: Expected 'styles' to be an array of strings.
  </code></pre>
  
  <p>I have tried various configurations in my webpack config, and am currently going with this:</p>
  
  <pre><code>{ 
      test: /\.css$/, 
      loaders: ['to-string-loader', 'css-loader'] 
  },
  {
      test: /\.scss$/,
      use: ['style-loader', 'css-loader', 'sass-loader'],
      include: [helpers.root( 'src', 'styles' )]
  }
  </code></pre>
  
  <p>There are a handful of references to this error on the interweb but none of them solve my problem. Any ideas how to fix this?</p>