Recently debsecan started blocking forever waiting for network requests
that never seem to complete. This is probably an issue with the
security-tracker CDN but I think that debsecan needs to cope with
issues in the network in a few different ways:

* Add a timeout so network issues do not block debsecan from exiting
* Add a debug option that explains what debsecan is doing (URLs etc)
* When on a terminal, print a progress bar for any downloads that occur