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

library/ezyang/htmlpurifier/library/HTMLPurifier/AttrDef/CSS/Multiple.php

@@ -1,71 +0,0 @@
-<?php
-
-/**
- * Framework class for strings that involve multiple values.
- *
- * Certain CSS properties such as border-width and margin allow multiple
- * lengths to be specified.  This class can take a vanilla border-width
- * definition and multiply it, usually into a max of four.
- *
- * @note Even though the CSS specification isn't clear about it, inherit
- *       can only be used alone: it will never manifest as part of a multi
- *       shorthand declaration.  Thus, this class does not allow inherit.
- */
-class HTMLPurifier_AttrDef_CSS_Multiple extends HTMLPurifier_AttrDef
-{
-    /**
-     * Instance of component definition to defer validation to.
-     * @type HTMLPurifier_AttrDef
-     * @todo Make protected
-     */
-    public $single;
-
-    /**
-     * Max number of values allowed.
-     * @todo Make protected
-     */
-    public $max;
-
-    /**
-     * @param HTMLPurifier_AttrDef $single HTMLPurifier_AttrDef to multiply
-     * @param int $max Max number of values allowed (usually four)
-     */
-    public function __construct($single, $max = 4)
-    {
-        $this->single = $single;
-        $this->max = $max;
-    }
-
-    /**
-     * @param string $string
-     * @param HTMLPurifier_Config $config
-     * @param HTMLPurifier_Context $context
-     * @return bool|string
-     */
-    public function validate($string, $config, $context)
-    {
-        $string = $this->mungeRgb($this->parseCDATA($string));
-        if ($string === '') {
-            return false;
-        }
-        $parts = explode(' ', $string); // parseCDATA replaced \r, \t and \n
-        $length = count($parts);
-        $final = '';
-        for ($i = 0, $num = 0; $i < $length && $num < $this->max; $i++) {
-            if (ctype_space($parts[$i])) {
-                continue;
-            }
-            $result = $this->single->validate($parts[$i], $config, $context);
-            if ($result !== false) {
-                $final .= $result . ' ';
-                $num++;
-            }
-        }
-        if ($final === '') {
-            return false;
-        }
-        return rtrim($final);
-    }
-}
-
-// vim: et sw=4 sts=4