(chore) Refactors to support PHP 7.3

If you upgrade to php@7.2, phpspec will start failing because Minds\Entities\Object is now a reserved word. It won't even compile.

There are various additional errors that need resolving to upgrade to PHP 7.3...

• Use of continue in case statements that need replacing with either break or continue 2
• method signatures of classes that are extending an abstract class where the new method signatures do not match the method signatures of the abstract