Various timeouts and download problems with FTP updater

Difficult to tell what the issue is...

• It doesn't happen with everyone
• When it happens, downloads stop completely, timeout, and it switches to the next file

Is it because of FTP for some people? The basic-ftp module perhaps? Should we try something different like Webdav?

Note that with the download system rewrite due for karoakmugen/karaokemugen-server, this might not be a problem anymore.