PhpStorm inspections

Fixed some minor bugs and dropped some obsolete code

pocketmine\level\generator namespace is ignored in this commit

src/pocketmine/event/Event.php

@@ -63,8 +63,6 @@ abstract class Event{
 	/**
 	 * @param bool $value
 	 *
-	 * @return bool
-	 *
 	 * @throws \BadMethodCallException
 	 */
 	public function setCancelled($value = true){