Clean-up of time handling and time formatting functions. Essentially,
lyskom-format-time, lyskom-client-date-string and lyskom-return-date-and-time have been replaced with a single function: lyskom-format-time. Also, the internal time representation now has years that are relative to year 0 and months that start with 1 for January. New variables: kom-print-relative-dates and kom-print-seconds-in-time-strings.