Catch Ctrl c

[AndreasGocht]

Some ml stuff needs to be interrupted using ctrl-c. We should catch this, and writ traces.

[AndreasGocht]

There are two ways doing this:

• use the associated KeyboardInterrupt exception, or use
• implement a SIGUSR1 handler using signal.signal

[AndreasGocht]

maybe use

/**
 * Finalize the measurement system. This function @e may be called from the
 * adapter layer (or implicitly by at_exit). Calling other API functions
 * afterwards is seen as undefined behaviour.
 *
 * Calling this function several times does no harm to the measurement system.
 *
 * @see SCOREP_InitMeasurement()
 */
void
SCOREP_FinalizeMeasurement( void );