Bump to API 3.0.0-ALPHA2 - READ DESCRIPTION!

Refactored level\format\generic\GenericChunk -> level\format\Chunk.
Re-added support for async chunk sending
Refactored most Level IO into new namespaces for more organisation
Removed LevelDB loader completely (will be re-added at a later date)

src/pocketmine/level/format/io/LevelProviderManager.php

@@ -0,0 +1,72 @@
+<?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\level\format\io;
+
+use pocketmine\utils\LevelException;
+
+abstract class LevelProviderManager{
+	protected static $providers = [];
+
+	/**
+	 * @param string $class
+	 *
+	 * @throws LevelException
+	 */
+	public static function addProvider(string $class){
+		if(!is_subclass_of($class, LevelProvider::class)){
+			throw new LevelException("Class is not a subclass of LevelProvider");
+		}
+		/** @var LevelProvider $class */
+		self::$providers[strtolower($class::getProviderName())] = $class;
+	}
+
+	/**
+	 * Returns a LevelProvider class for this path, or null
+	 *
+	 * @param string $path
+	 *
+	 * @return string|null
+	 */
+	public static function getProvider(string $path){
+		foreach(self::$providers as $provider){
+			/** @var $provider LevelProvider */
+			if($provider::isValid($path)){
+				return $provider;
+			}
+		}
+
+		return null;
+	}
+
+	/**
+	 * Returns a LevelProvider by name, or null if not found
+	 *
+	 * @param string $name
+	 *
+	 * @return string|null
+	 */
+	public static function getProviderByName(string $name){
+		return self::$providers[trim(strtolower($name))] ?? null;
+	}
+}