Added small benchmark

src/pocketmine/math/AxisAlignedBB.php

@@ -21,7 +21,10 @@
 
 namespace pocketmine\math;
 
-
+/**
+ * WARNING: This class is available on the PocketMine-MP Zephir project.
+ * If this class is modified, remember to modify the PHP C extension.
+ */
 class AxisAlignedBB{
 	public $minX;
 	public $minY;