trafgen: Exit gracefully for all possible termination signals

Handle all termination signals that we're allowed to handle (SIGKILL
can't be handled) in order to exit gracefully in any regular termination
case.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
astraceroute: Exit gracefully for all possible termination signals

Handle all termination signals that we're allowed to handle (SIGKILL
can't be handled) in order to exit gracefully in any regular termination
case.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
flowtop: Exit gracefully for all possible termination signals

Handle all termination signals that we're allowed to handle (SIGKILL
can't be handled) in order to exit gracefully in any regular termination
case.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
ifpps: Exit gracefully for all possible termination signals

Handle all termination signals that we're allowed to handle (SIGKILL
can't be handled) in order to exit gracefully in any regular termination
case.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>