Exercise: Catching Ctrl-C on Unix 2nd time

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• When Ctrl-C is pressed display: "In order to really kill the application press Ctrl-C again" and keep running. If the user presses Ctrl-C again, then let id die.
• Improve the previous that if 5 sec within the first Ctrl-C there is no 2nd Ctrl-C then any further Ctrl-C will trigger the above message again.