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/URIScheme/ftp.php

@@ -0,0 +1,58 @@
+<?php
+
+/**
+ * Validates ftp (File Transfer Protocol) URIs as defined by generic RFC 1738.
+ */
+class HTMLPurifier_URIScheme_ftp extends HTMLPurifier_URIScheme
+{
+    /**
+     * @type int
+     */
+    public $default_port = 21;
+
+    /**
+     * @type bool
+     */
+    public $browsable = true; // usually
+
+    /**
+     * @type bool
+     */
+    public $hierarchical = true;
+
+    /**
+     * @param HTMLPurifier_URI $uri
+     * @param HTMLPurifier_Config $config
+     * @param HTMLPurifier_Context $context
+     * @return bool
+     */
+    public function doValidate(&$uri, $config, $context)
+    {
+        $uri->query = null;
+
+        // typecode check
+        $semicolon_pos = strrpos($uri->path, ';'); // reverse
+        if ($semicolon_pos !== false) {
+            $type = substr($uri->path, $semicolon_pos + 1); // no semicolon
+            $uri->path = substr($uri->path, 0, $semicolon_pos);
+            $type_ret = '';
+            if (strpos($type, '=') !== false) {
+                // figure out whether or not the declaration is correct
+                list($key, $typecode) = explode('=', $type, 2);
+                if ($key !== 'type') {
+                    // invalid key, tack it back on encoded
+                    $uri->path .= '%3B' . $type;
+                } elseif ($typecode === 'a' || $typecode === 'i' || $typecode === 'd') {
+                    $type_ret = ";type=$typecode";
+                }
+            } else {
+                $uri->path .= '%3B' . $type;
+            }
+            $uri->path = str_replace(';', '%3B', $uri->path);
+            $uri->path .= $type_ret;
+        }
+        return true;
+    }
+}
+
+// vim: et sw=4 sts=4