Update Smarty to 3.1.21

- add missing block.tphp, block.textformat.php, function.popup.php,
  function.popup_init.php
- update function in function.html_checkboxes.php,
  function.html_options.php

www/Smarty-3.1.21/plugins/shared.escape_special_chars.php

@@ -0,0 +1,53 @@
+<?php
+/**
+ * Smarty shared plugin
+ *
+ * @package    Smarty
+ * @subpackage PluginsShared
+ */
+
+if (version_compare(PHP_VERSION, '5.2.3', '>=')) {
+    /**
+     * escape_special_chars common function
+     * Function: smarty_function_escape_special_chars<br>
+     * Purpose:  used by other smarty functions to escape
+     *           special chars except for already escaped ones
+     *
+     * @author   Monte Ohrt <monte at ohrt dot com>
+     *
+     * @param  string $string text that should by escaped
+     *
+     * @return string
+     */
+    function smarty_function_escape_special_chars($string)
+    {
+        if (!is_array($string)) {
+            $string = htmlspecialchars($string, ENT_COMPAT, Smarty::$_CHARSET, false);
+        }
+
+        return $string;
+    }
+} else {
+    /**
+     * escape_special_chars common function
+     * Function: smarty_function_escape_special_chars<br>
+     * Purpose:  used by other smarty functions to escape
+     *           special chars except for already escaped ones
+     *
+     * @author   Monte Ohrt <monte at ohrt dot com>
+     *
+     * @param  string $string text that should by escaped
+     *
+     * @return string
+     */
+    function smarty_function_escape_special_chars($string)
+    {
+        if (!is_array($string)) {
+            $string = preg_replace('!&(#?\w+);!', '%%%SMARTY_START%%%\\1%%%SMARTY_END%%%', $string);
+            $string = htmlspecialchars($string);
+            $string = str_replace(array('%%%SMARTY_START%%%', '%%%SMARTY_END%%%'), array('&', ';'), $string);
+        }
+
+        return $string;
+    }
+}