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/AttrDef/URI/IPv6.php

@@ -0,0 +1,89 @@
+<?php
+
+/**
+ * Validates an IPv6 address.
+ * @author Feyd @ forums.devnetwork.net (public domain)
+ * @note This function requires brackets to have been removed from address
+ *       in URI.
+ */
+class HTMLPurifier_AttrDef_URI_IPv6 extends HTMLPurifier_AttrDef_URI_IPv4
+{
+
+    /**
+     * @param string $aIP
+     * @param HTMLPurifier_Config $config
+     * @param HTMLPurifier_Context $context
+     * @return bool|string
+     */
+    public function validate($aIP, $config, $context)
+    {
+        if (!$this->ip4) {
+            $this->_loadRegex();
+        }
+
+        $original = $aIP;
+
+        $hex = '[0-9a-fA-F]';
+        $blk = '(?:' . $hex . '{1,4})';
+        $pre = '(?:/(?:12[0-8]|1[0-1][0-9]|[1-9][0-9]|[0-9]))'; // /0 - /128
+
+        //      prefix check
+        if (strpos($aIP, '/') !== false) {
+            if (preg_match('#' . $pre . '$#s', $aIP, $find)) {
+                $aIP = substr($aIP, 0, 0 - strlen($find[0]));
+                unset($find);
+            } else {
+                return false;
+            }
+        }
+
+        //      IPv4-compatiblity check
+        if (preg_match('#(?<=:' . ')' . $this->ip4 . '$#s', $aIP, $find)) {
+            $aIP = substr($aIP, 0, 0 - strlen($find[0]));
+            $ip = explode('.', $find[0]);
+            $ip = array_map('dechex', $ip);
+            $aIP .= $ip[0] . $ip[1] . ':' . $ip[2] . $ip[3];
+            unset($find, $ip);
+        }
+
+        //      compression check
+        $aIP = explode('::', $aIP);
+        $c = count($aIP);
+        if ($c > 2) {
+            return false;
+        } elseif ($c == 2) {
+            list($first, $second) = $aIP;
+            $first = explode(':', $first);
+            $second = explode(':', $second);
+
+            if (count($first) + count($second) > 8) {
+                return false;
+            }
+
+            while (count($first) < 8) {
+                array_push($first, '0');
+            }
+
+            array_splice($first, 8 - count($second), 8, $second);
+            $aIP = $first;
+            unset($first, $second);
+        } else {
+            $aIP = explode(':', $aIP[0]);
+        }
+        $c = count($aIP);
+
+        if ($c != 8) {
+            return false;
+        }
+
+        //      All the pieces should be 16-bit hex strings. Are they?
+        foreach ($aIP as $piece) {
+            if (!preg_match('#^[0-9a-fA-F]{4}$#s', sprintf('%04s', $piece))) {
+                return false;
+            }
+        }
+        return $original;
+    }
+}
+
+// vim: et sw=4 sts=4