Update minifyx.class.php

$dir = str_replace('//', '/', '/' . $this->config['munee_cache'] .'/' ); 
this version do not work on windows, so but 
$dir = str_replace('//', '/', $this->config['munee_cache']); 
works both on win and linux
Merge pull request #11 from manicko/patch-1

Update minifyx.class.php