* init empty vars to avoid PHP8 warnings
* removed debug output for serendipity_session_destroy()
* init smarty fixed for PHP8
* removed optional parameters for PHP 8
* 2k11 template fixes, maybe updating smarty will solve everything
* init or test undefined variables for PHP 8
* remove only existing files
* make sure string is not empty before comparing the first letter
* check if SMARTY_DIR was already defined
* use mb_language('uni') for unicode
* fixed image filter bug
* Smarty debug fixed in external lib
* fixed archive bug
* fixed entries bug
* updated plugin versions
Co-authored-by: surrim <surrim@happyhydro.org>
PHP 5.4 sets UTF-8 as the default for htmlspecialchars, htmlentities and html_entity_decode. The first two will echo an empty string when given a string with umlauts. This commits introduces serendipity_specialchar-wrapper that are meant to be a temporary solution for the s9y-core until PHP 5.6 fixed the bug, so the native charset option of s9y continues to work.
