Use Composer autoload to handle dependency class loading

apps/bootstrap/index.php

 <?php
-
+// Set to false to disable debug mode
 defined('YII_DEBUG') or define('YII_DEBUG', true);
 
-require(__DIR__ . '/../../framework/yii.php');
+$frameworkPath = __DIR__ . '/../../framework/';
+require($frameworkPath . 'yii.php');
 
 $config = require(__DIR__ . '/protected/config/main.php');
 $application = new yii\web\Application($config);
+
+// Register Composer autoloader
+@include $frameworkPath . '/vendor/autoload.php';
+
 $application->run();

framework/helpers/base/Markdown.php

@@ -7,7 +7,6 @@
 
 namespace yii\helpers\base;
 
-\Yii::setAlias('@Michelf', \Yii::getAlias('@yii/vendor/michelf/php-markdown/Michelf'));
 use Michelf\MarkdownExtra;
 
 /**

framework/helpers/base/Purifier.php

@@ -6,10 +6,6 @@
  */
 namespace yii\helpers\base;
 
-if (!class_exists('HTMLPurifier_Bootstrap', false)) {
-	require_once(\Yii::getAlias('@yii/vendor/ezyang/htmlpurifier/library/HTMLPurifier.auto.php'));
-}
-
 /**
  * Purifier provides an ability to clean up HTML from any harmful code.
  *

framework/renderers/SmartyViewRenderer.php

@@ -24,11 +24,6 @@ use yii\helpers\Html;
 class SmartyViewRenderer extends ViewRenderer
 {
 	/**
-	 * @var string the directory or path alias pointing to where Smarty code is located.
-	 */
-	public $smartyPath = '@yii/vendor/smarty/smarty/distribution/libs';
-
-	/**
 	 * @var string the directory or path alias pointing to where Smarty cache will be stored.
 	 */
 	public $cachePath = '@app/runtime/Smarty/cache';
@@ -45,7 +40,6 @@ class SmartyViewRenderer extends ViewRenderer
 
 	public function init()
 	{
-		require_once(Yii::getAlias($this->smartyPath) . '/Smarty.class.php');
 		$this->smarty = new Smarty();
 		$this->smarty->setCompileDir(Yii::getAlias($this->compilePath));
 		$this->smarty->setCacheDir(Yii::getAlias($this->cachePath));

framework/renderers/TwigViewRenderer.php

@@ -23,11 +23,6 @@ use yii\helpers\Html;
 class TwigViewRenderer extends ViewRenderer
 {
 	/**
-	 * @var string the directory or path alias pointing to where Twig code is located.
-	 */
-	public $twigPath = '@yii/vendor/twig/twig/lib/Twig';
-
-	/**
 	 * @var string the directory or path alias pointing to where Twig cache will be stored.
 	 */
 	public $cachePath = '@app/runtime/Twig/cache';
@@ -45,10 +40,6 @@ class TwigViewRenderer extends ViewRenderer
 
 	public function init()
 	{
-		if (!isset(Yii::$aliases['@Twig'])) {
-			Yii::setAlias('@Twig', $this->twigPath);
-		}
-
 		$loader = new \Twig_Loader_String();
 
 		$this->twig = new \Twig_Environment($loader, array_merge(array(