Added the option to configure the format in which appointment time is
displayed. The setting is called "format.appointmenttime" under the
general settings menu. Setting defaults to previous behavior, which was
"%H:%M".
Signed-off-by: mercurialmoon <mercurialmoon@protonmail.com>
Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>
