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/ChildDef/StrictBlockquote.php

@@ -0,0 +1,110 @@
+<?php
+
+/**
+ * Takes the contents of blockquote when in strict and reformats for validation.
+ */
+class HTMLPurifier_ChildDef_StrictBlockquote extends HTMLPurifier_ChildDef_Required
+{
+    /**
+     * @type array
+     */
+    protected $real_elements;
+
+    /**
+     * @type array
+     */
+    protected $fake_elements;
+
+    /**
+     * @type bool
+     */
+    public $allow_empty = true;
+
+    /**
+     * @type string
+     */
+    public $type = 'strictblockquote';
+
+    /**
+     * @type bool
+     */
+    protected $init = false;
+
+    /**
+     * @param HTMLPurifier_Config $config
+     * @return array
+     * @note We don't want MakeWellFormed to auto-close inline elements since
+     *       they might be allowed.
+     */
+    public function getAllowedElements($config)
+    {
+        $this->init($config);
+        return $this->fake_elements;
+    }
+
+    /**
+     * @param array $children
+     * @param HTMLPurifier_Config $config
+     * @param HTMLPurifier_Context $context
+     * @return array
+     */
+    public function validateChildren($children, $config, $context)
+    {
+        $this->init($config);
+
+        // trick the parent class into thinking it allows more
+        $this->elements = $this->fake_elements;
+        $result = parent::validateChildren($children, $config, $context);
+        $this->elements = $this->real_elements;
+
+        if ($result === false) {
+            return array();
+        }
+        if ($result === true) {
+            $result = $children;
+        }
+
+        $def = $config->getHTMLDefinition();
+        $block_wrap_name = $def->info_block_wrapper;
+        $block_wrap = false;
+        $ret = array();
+
+        foreach ($result as $node) {
+            if ($block_wrap === false) {
+                if (($node instanceof HTMLPurifier_Node_Text && !$node->is_whitespace) ||
+                    ($node instanceof HTMLPurifier_Node_Element && !isset($this->elements[$node->name]))) {
+                        $block_wrap = new HTMLPurifier_Node_Element($def->info_block_wrapper);
+                        $ret[] = $block_wrap;
+                }
+            } else {
+                if ($node instanceof HTMLPurifier_Node_Element && isset($this->elements[$node->name])) {
+                    $block_wrap = false;
+
+                }
+            }
+            if ($block_wrap) {
+                $block_wrap->children[] = $node;
+            } else {
+                $ret[] = $node;
+            }
+        }
+        return $ret;
+    }
+
+    /**
+     * @param HTMLPurifier_Config $config
+     */
+    private function init($config)
+    {
+        if (!$this->init) {
+            $def = $config->getHTMLDefinition();
+            // allow all inline elements
+            $this->real_elements = $this->elements;
+            $this->fake_elements = $def->info_content_sets['Flow'];
+            $this->fake_elements['#PCDATA'] = true;
+            $this->init = true;
+        }
+    }
+}
+
+// vim: et sw=4 sts=4