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/Name.php

@@ -0,0 +1,26 @@
+<?php
+
+class HTMLPurifier_HTMLModule_Name extends HTMLPurifier_HTMLModule
+{
+    /**
+     * @type string
+     */
+    public $name = 'Name';
+
+    /**
+     * @param HTMLPurifier_Config $config
+     */
+    public function setup($config)
+    {
+        $elements = array('a', 'applet', 'form', 'frame', 'iframe', 'img', 'map');
+        foreach ($elements as $name) {
+            $element = $this->addBlankElement($name);
+            $element->attr['name'] = 'CDATA';
+            if (!$config->get('HTML.Attr.Name.UseCDATA')) {
+                $element->attr_transform_post[] = new HTMLPurifier_AttrTransform_NameSync();
+            }
+        }
+    }
+}
+
+// vim: et sw=4 sts=4