Catch KeyboardInterrupt for nicer ^C

Signed-off-by: Maxime Petazzoni <max@signalfuse.com>
Simplify and speed-up container ping logic

Signed-off-by: Maxime Petazzoni <max@signalfuse.com>
Improve port status display in fullstatus

Signed-off-by: Maxime Petazzoni <max@signalfuse.com>