Added S2C and C2S handshake packet classes and stub handlers

TODO: implement encryption

Add boilerplate reset() for C2S packet encode

This crap really needs fixing

src/pocketmine/network/mcpe/protocol/ServerToClientHandshakePacket.php

@@ -0,0 +1,49 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+namespace pocketmine\network\mcpe\protocol;
+
+#include <rules/DataPacket.h>
+
+
+use pocketmine\network\mcpe\NetworkSession;
+
+class ServerToClientHandshakePacket extends DataPacket{
+	const NETWORK_ID = ProtocolInfo::SERVER_TO_CLIENT_HANDSHAKE_PACKET;
+
+	public $publicKey;
+	public $serverToken;
+
+	public function decode(){
+		$this->publicKey = $this->getString();
+		$this->serverToken = $this->getString();
+	}
+
+	public function encode(){
+		$this->reset();
+		$this->putString($this->publicKey);
+		$this->putString($this->serverToken);
+	}
+
+	public function handle(NetworkSession $session) : bool{
+		return $session->handleServerToClientHandshake($this);
+	}
+}