Rollback laracast authentication, implement Sentry 2.

Not shown: In app/config/app.php
Add 'Cartalyst\Sentry\SentryServiceProvider' to providers array,
Add 'Sentry' => 'Cartalyst\Sentry\Facades\Laravel\Sentry' to aliases
array,
Run `php artisan migrate --package=cartalyst/sentry` after the rollback.