Revert "remove htmlpurifier"

This reverts commit c21a462d52.

lib/htmlpurifier/library/HTMLPurifier/Strategy/Composite.php

@@ -0,0 +1,23 @@
+<?php
+
+/**
+ * Composite strategy that runs multiple strategies on tokens.
+ */
+abstract class HTMLPurifier_Strategy_Composite extends HTMLPurifier_Strategy
+{
+
+    /**
+     * List of strategies to run tokens through.
+     */
+    protected $strategies = array();
+
+    public function execute($tokens, $config, $context) {
+        foreach ($this->strategies as $strategy) {
+            $tokens = $strategy->execute($tokens, $config, $context);
+        }
+        return $tokens;
+    }
+
+}
+
+// vim: et sw=4 sts=4