Change from Gregorian to Julian calendar in Qt 4.2

[David Jarvie]

In the latest Qt 4.2 changes, QDate now uses the Julian calendar instead of the Gregorian for dates before 1582. In some ways, this makes 
even more of a mess of date handling than before due to the two calendar systems. Now, QDate uses Julian dates pre-1582 - which don't 
necessarily coincide with historical records since usage of the calendar wasn't properly standardised. It uses Gregorian dates post-1582 - but 
because most countries didn't adopt the Gregorian calendar until long after 1582, this often doesn't coincide with historical records either until 
the 20th century. For scientific purposes, the Gregorian calendar is universally used both pre- and post-1582.

The question for KDE is, should the KDateTime class follow QDate in the switch to the Julian calendar (which will happen automatically as things 
stand since it uses QDateTime internally), or should it be changed to use a different internal representation for date/time values so as to 
continue to use the Gregorian calendar throughout?

--
David Jarvie.