Apparently, the components of origin are used as positional rather than
as named!  I.e.,
	options(chron.origin = c(month = 1, day = 1, year = 1960))
is ok but
	options(chron.origin = c(year = 1960, month = 1, day = 1))
is not.  DEBUG etc etc

How can we improve the handling of holidays?