Add the vanilla version of the project

This version can still be found here:

http://www.roland-riegel.de/nload/index.html
prevent a crash when sysfs and proc are not readable

The program used to return an empty list of devices.
Nevertheless, the method printTraffic of TrafficWindow does not handle
empty lists.

Fixed by throwing an exception whenever proc and sysfs are both
unaccessible.

Signed-off-by: Olivier Gayot <duskcoder@gmail.com>