Date functions

[Michael Vogel]

I'll try to use PB commands whenever possible, so I thought also ParseDate, Date etc. could be used for "calculating" with time elements. But it seems to be that only dates from 1980 or so deliver results (so it's impossible to use the routines for calculating how old I am in seconds;)

Seriously, it would be simple to use the same internal math for earlier dates (lets say beginning from 1583/01/01) and I would have no problem if the date() results can be also negative numbers for compatibility reasons...