Modify impressConsole to work without requiring configuration parameter

[henrikingo]

Currently impressConsole requires a path to its cssFile to work. After adding the src/plugins/extras/ plugin we pass it thusly:

<script type="text/javascript" src="../../extras/impress-console/js/impressConsole.js"></script>
  <script type="text/javascript">
  // For impressConsole, we unfortunately must also set the path to a mandatory css file
  // which is relative to this html file.
  // See https://github.com/regebro/impress-console/issues/19
  var impressConsoleCss = '../../extras/impress-console/css/impressConsole.css';
</script>

TODO

• Create a patch on impressConsole to have minimal CSS inline, so that it works sanely without providing an external CSS file.
• Submit PR against impressConsole repo.
  • If they wouldn't accept it, maintain a fork.

For more context, see regebro/impress-console#19

[henrikingo]

This was done in c10c999