Failsafe if the user isn't set on a revision to use empty string.
Fixes #308

Adding additional tests to cover the removal of multiple tags at once. And making sure all tag links have been removed upon removing an entity.

The orWhere statement caused tags not to be found. Fixed issue when having an entity with 3 tags, updating it with 0 tags, remove all 3 links. This wasn't the case before.

 in 5.4 this broke and isn't searching for the id column and not the key column.

Laravel 5.4 compatibility

Wildcard listener can now listen directly to an interface, that events are implementing.

See https://laravel.com/docs/5.4/upgrade

>set() method should be changed to ->put()

....

Sessions:Symfony Compatibility

Laravel's session handlers no longer implements Symfony's SessionInterface. Implementing this interface required us to implement extraneous features that were not needed by the framework. Instead, a new Illuminate\Contracts\Session\Session interface has been defined and may be used instead. The following code changes should also be applied:

All calls to the ->set() method should be changed to ->put(). Typically, Laravel applications would never call the set method since it has never been documented within the Laravel documentation. However, it is included here out of caution.

All calls to the ->getToken() method should be changed to ->token().

All calls to the $request->setSession() method should be changed to setLaravelSession().