TODO for net_monitor:

 - show advanced values (netmask, broadcast, MTU, flags, ...)
 - implement advanced logging (start and stop counting network transfers,
   accounting number of packets, bytes, and so on)
 - correctly detect when device is active
 - highlight interfaces with higher transmission rate
 - wireless: show essid and signal level when available (/proc/net/wireless)
 - network info: show gateway, routes and dns info (/proc/net/routes)
 - auto-detect new and removed interfaces (ppp0, etc)