Improve checks for Position::equals() and Location::equals() (#929)

* Add files via upload

* Position::$level can be null.

* Use getLevel() in place of $level

because of WeakPosition.

src/pocketmine/level/Position.php

@@ -133,4 +133,10 @@ class Position extends Vector3{
 		return $this;
 	}
 
+	public function equals(Vector3 $v){
+		if($v instanceof Position){
+			return parent::equals($v) and $v->getLevel() === $this->getLevel();
+		}
+		return parent::equals($v);
+	}
 }