title: @angular/material no exported member 'OverlayContainer'
body: <p>I'm trying to get custom theming working and everything is ok until I need to style the OverlayContainer for dialogs and modals. When I try to import OverlayContainer as per the documentation and various guides VS Code throws an error:</p>
  
  <p><code>Module '../node_modules/@angular/material/material"' has no exported member 'OverlayContainer'</code>)</p>
  
  <p>I've tried searching through the node_modules folder in case its just in a different directory but it appears not.</p>
  
  <p>What am I missing? Any help appreciated.</p>
  
  <p>app.component.ts</p>
  
  <pre><code>import { OverlayContainer } from '@angular/material';
  </code></pre>
  
  <p>package.json</p>
  
  <p><code>"@angular/material": "^5.0.0-rc.2"</code></p>