new feature (default gw flag, status tab), fixed log timestamp & more

See this thread for more details:
http://forums.openmediavault.org/index.php/Thread/5801-OpenVPN-plugin-enhancement-and-issues/
Instead of reading files with cat and exec you could just simply use file_get_contents($path) here. 

I'm not really sure you need to use gettext here since I would guess that part won't get translated, but it doesn't matter much.