* lisp/calendar/timeclock.el: Minor cleanups.
(timeclock-ask-before-exiting, timeclock-use-display-time): Use `symbol'.
(timeclock-modeline-display): Define as alias before the actual definition.
(timeclock-mode-line-display): Use define-minor-mode.
(timeclock-day-list-template): Make it a function, add an argument.
(timeclock-day-list-required, timeclock-day-list-length)
(timeclock-day-list-debt, timeclock-day-list-span)
(timeclock-day-list-break): Adjust calls accordingly.