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/URIParser.php

@@ -0,0 +1,71 @@
+<?php
+
+/**
+ * Parses a URI into the components and fragment identifier as specified
+ * by RFC 3986.
+ */
+class HTMLPurifier_URIParser
+{
+
+    /**
+     * Instance of HTMLPurifier_PercentEncoder to do normalization with.
+     */
+    protected $percentEncoder;
+
+    public function __construct()
+    {
+        $this->percentEncoder = new HTMLPurifier_PercentEncoder();
+    }
+
+    /**
+     * Parses a URI.
+     * @param $uri string URI to parse
+     * @return HTMLPurifier_URI representation of URI. This representation has
+     *         not been validated yet and may not conform to RFC.
+     */
+    public function parse($uri)
+    {
+        $uri = $this->percentEncoder->normalize($uri);
+
+        // Regexp is as per Appendix B.
+        // Note that ["<>] are an addition to the RFC's recommended
+        // characters, because they represent external delimeters.
+        $r_URI = '!'.
+            '(([a-zA-Z0-9\.\+\-]+):)?'. // 2. Scheme
+            '(//([^/?#"<>]*))?'. // 4. Authority
+            '([^?#"<>]*)'.       // 5. Path
+            '(\?([^#"<>]*))?'.   // 7. Query
+            '(#([^"<>]*))?'.     // 8. Fragment
+            '!';
+
+        $matches = array();
+        $result = preg_match($r_URI, $uri, $matches);
+
+        if (!$result) return false; // *really* invalid URI
+
+        // seperate out parts
+        $scheme     = !empty($matches[1]) ? $matches[2] : null;
+        $authority  = !empty($matches[3]) ? $matches[4] : null;
+        $path       = $matches[5]; // always present, can be empty
+        $query      = !empty($matches[6]) ? $matches[7] : null;
+        $fragment   = !empty($matches[8]) ? $matches[9] : null;
+
+        // further parse authority
+        if ($authority !== null) {
+            $r_authority = "/^((.+?)@)?(\[[^\]]+\]|[^:]*)(:(\d*))?/";
+            $matches = array();
+            preg_match($r_authority, $authority, $matches);
+            $userinfo   = !empty($matches[1]) ? $matches[2] : null;
+            $host       = !empty($matches[3]) ? $matches[3] : '';
+            $port       = !empty($matches[4]) ? (int) $matches[5] : null;
+        } else {
+            $port = $host = $userinfo = null;
+        }
+
+        return new HTMLPurifier_URI(
+            $scheme, $userinfo, $host, $port, $path, $query, $fragment);
+    }
+
+}
+
+// vim: et sw=4 sts=4