added throwable eggs and refactor some projectile logic

close #1473

src/pocketmine/entity/projectile/Egg.php

@@ -0,0 +1,45 @@
+<?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/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+namespace pocketmine\entity\projectile;
+
+use pocketmine\network\mcpe\protocol\AddEntityPacket;
+use pocketmine\Player;
+
+class Egg extends Throwable{
+	const NETWORK_ID = 82;
+
+	public function spawnTo(Player $player){
+		$pk = new AddEntityPacket();
+		$pk->type = Egg::NETWORK_ID;
+		$pk->entityRuntimeId = $this->getId();
+		$pk->position = $this->asVector3();
+		$pk->motion = $this->getMotion();
+		$pk->metadata = $this->dataProperties;
+		$player->dataPacket($pk);
+
+		parent::spawnTo($player);
+	}
+
+	//TODO: spawn chickens on collision
+}