[Gretl-devel] RFC: gretl calendar

Further follow-up to Ignacio's comment in http://lists.wfu.edu/pipermail/gretl-devel/2017-February/007439.html (As a reminder, Ignacio remarked that gretl was considering 1700 as a leap year, which it wasn't on the Gregorian calendar, and also that our weekday() function was producing some bad values for eighteenth century dates.) In git and snapshots I've now revamped gretl's calendar so that it's consistently Gregorian by default. At the same time I've added some apparatus for handling Julian dates, in case that should be needed for dealing with historical data. Internally, we're now using GLib's GDate API (with some additional algorithms for handling Julian dates) in place of the old code based on the unix "cal" program. The current setup is discussed in a new chapter 16, "Calendar dates", in the User's Guide. I've partially updated the help for the relevant calendrical functions in line with the new chapter, but not yet fully since I'd like to wait and get people's reactions. So, comments welcome. Allin