* calendar.el (calendar-version): Update to 5.1. Fixed a variety

* calendar.el (calendar-version): Update to 5.1.  Fixed a variety
        of spelling error in comments and doc strings.
        (calendar-sexp-debug): New variable to turn off error catching.
	(calendar-absolute-from-gregorian): Removed unused vars month, day.
        (view-calendar-holidays-initially, all-hebrew-calendar-holidays,
        all-christian-calendar-holidays, all-christian-islamic-holidays,
        diary-nonmarking-symbol, hebrew-diary-entry-symbol,
        islamic-diary-entry-symbol, diary-include-string,
        abbreviated-calendar-year, european-calendar-style,
        european-calendar-display-form, american-calendar-display-form,
        calendar-date-display-form, print-diary-entries-hook,
        list-diary-entries-hook, nongregorian-diary-listing-hook,
        nongregorian-diary-marking-hook, diary-list-include-blanks,
        holidays-in-diary-buffer, general-holidays,
        increment-calendar-month, calendar-sum, calendar-string-spread,
        calendar-absolute-from-iso, calendar-print-iso-date,
        hebrew-calendar-elapsed-days, list-yahrzeit-dates,
        calendar-print-astro-day-number): Fix doc strings.
        (calendar-nth-named-day): Rewritten to include optional day of month.
        (general-holidays, calendar-holidays, hebrew-holidays,
        christian-holidays, islamic-holidays,
        solar-holidays): Rewritten to include require of cal-dst.el and to
        show the time of the change to/from daylight savings time.
        (calendar-current-time-zone, calendar-time-zone,
        calendar-daylight-time-offset, calendar-standard-time-zone-name,
        calendar-daylight-time-zone-name, calendar-daylight-savings-starts,
        calendar-daylight-savings-ends,
        calendar-daylight-savings-switchover-time): Moved to cal-dst.el.
        (calendar-location-name, calendar-time-display-form, calendar-latitude,
        calendar-longitude): Moved to solar.el.
        (calendar-holidays): Unquote it!