Replace existing autoloader with Composer-supplied

- Move Friendica namespace to `src`
- Move required `ezyang/htmlpurifier` to vendor
- Remove existing static autoloader
- Change boot.php reference to the autoloader

vendor/ezyang/htmlpurifier/library/HTMLPurifier/HTMLModule/StyleAttribute.php

@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * XHTML 1.1 Edit Module, defines editing-related elements. Text Extension
+ * Module.
+ */
+class HTMLPurifier_HTMLModule_StyleAttribute extends HTMLPurifier_HTMLModule
+{
+    /**
+     * @type string
+     */
+    public $name = 'StyleAttribute';
+
+    /**
+     * @type array
+     */
+    public $attr_collections = array(
+        // The inclusion routine differs from the Abstract Modules but
+        // is in line with the DTD and XML Schemas.
+        'Style' => array('style' => false), // see constructor
+        'Core' => array(0 => array('Style'))
+    );
+
+    /**
+     * @param HTMLPurifier_Config $config
+     */
+    public function setup($config)
+    {
+        $this->attr_collections['Style']['style'] = new HTMLPurifier_AttrDef_CSS();
+    }
+}
+
+// vim: et sw=4 sts=4