Add a rebuild command

Now that https://drupal.org/node/2097189 is done, we now have a drupal_rebuild() function that we can use to rebuild the DIC, twig dumped php caches, and regular caches.

If you have an out of date container or something, this is a must to quickly get your working again. So we might as well have a drush command for this too that utilises this as well as the rebuild.php script that ships with D8.