Use `cl-lib'.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
Update Copyright.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
Add missing customization types.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>