Revert "remove htmlpurifier"

This reverts commit c21a462d52.

lib/htmlpurifier/library/HTMLPurifier/Strategy.php

@@ -0,0 +1,26 @@
+<?php
+
+/**
+ * Supertype for classes that define a strategy for modifying/purifying tokens.
+ *
+ * While HTMLPurifier's core purpose is fixing HTML into something proper,
+ * strategies provide plug points for extra configuration or even extra
+ * features, such as custom tags, custom parsing of text, etc.
+ */
+
+
+abstract class HTMLPurifier_Strategy
+{
+
+    /**
+     * Executes the strategy on the tokens.
+     *
+     * @param $tokens Array of HTMLPurifier_Token objects to be operated on.
+     * @param $config Configuration options
+     * @returns Processed array of token objects.
+     */
+    abstract public function execute($tokens, $config, $context);
+
+}
+
+// vim: et sw=4 sts=4