'zlib output compression' handler

If you change zlib output compression setting in between ob_start, ob_end_clean or ob_end_flush (Smarty does this)
you will get: ob_end_flush() failed to delete buffer zlib output compression.

Workaround for smarty, added at line 1853: 

 else if ( $handler === 'zlib output compression' ) {
    if (ob_get_level()) {
        while (@ob_end_clean());
    }
 }

![smarty_ob](https://f.cloud.github.com/assets/1819668/1821896/c6aaf312-7146-11e3-888c-046a0bbaa929.jpg)