do not use iconv in tag_is_valid, data should be utf8 anyway at this point; remove sanity check for iconv because parser does not use it

include/functions.php

@@ -3039,10 +3039,6 @@
 		if (preg_match("/^[0-9]*$/", $tag)) return false;
 		if (mb_strlen($tag) > 250) return false;
 
-		if (function_exists('iconv')) {
-			$tag = iconv("utf-8", "utf-8", $tag);
-		}
-
 		if (!$tag) return false;
 
 		return true;

include/sanity_check.php

@@ -138,10 +138,6 @@
 				array_push($errors, "PHP support for ctype functions are required by HTMLPurifier.");
 			}
 
-			if (!function_exists("iconv")) {
-				array_push($errors, "PHP support for iconv is required to handle multiple charsets.");
-			}
-
 			/* if (ini_get("safe_mode")) {
 				array_push($errors, "PHP safe mode setting is not supported.");
 			} */