Prevent logout issue after page was cached (#1004)

Logout may not work otherwise, browser reloads cached page from disk instead of sending GET request ?logout=1 to server.

tinyfilemanager.php

@@ -222,7 +222,7 @@
  mb_regex_encoding('UTF-8');
  }
 
- session_cache_limiter('');
+ session_cache_limiter('nocache'); // Prevent logout issue after page was cached
  session_name(FM_SESSION_ID );
  function session_error_handling_function($code, $msg, $file, $line) {
  // Permission denied for default session, try to create a new one