Add new metadata type vector3f and correct metadata encoding. Result = client crash. TODO: new data values and flags.

src/pocketmine/entity/Entity.php

@@ -74,6 +74,7 @@ abstract class Entity extends Location implements Metadatable{
 	const DATA_TYPE_SLOT = 5;
 	const DATA_TYPE_POS = 6;
 	const DATA_TYPE_LONG = 7;
+	const DATA_TYPE_VECTOR3F = 8;
 
 	const DATA_FLAGS = 0;
 	const DATA_AIR = 1;