Reduce some cal-tex code duplication

Reduce some cal-tex code duplication

* lisp/calendar/cal-tex.el (cal-tex-filofax-paper): New function.
(cal-tex-cursor-filofax-year, cal-tex-cursor-filofax-2week)
(cal-tex-cursor-filofax-week, cal-tex-cursor-filofax-daily): Use it.
(cal-tex-weekly-paper): New function.
(cal-tex-cursor-week, cal-tex-cursor-week2)
(cal-tex-cursor-week-iso, cal-tex-cursor-week-monday)
(cal-tex-cursor-day): Use it.