Overview
 About the Date routines ("High Level"):
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 The Expand Library comprises 2 kinds of Date/Time functions.
 This 1st part are the "Low Level" functions, where all functions have been
 written in Assembly, and generally interface with the system.

 This part ("High Level") is more dedicated to functions to perform
 on date variables, and are written in Clipper.

 All functions accept one parameter, which must be a date variable, when
 omitted, date() is used instead (meaning today). The return types
 differ per function.

 This set of functions make some date fooling around possible, for instance,
 when writing that oh so popular calendar function.

 Note also the use of XPstod() to describe dates, as to avoid confusion with
 the way Europeans, Americans and Japanese (to name a few) represent dates.
 Dates are thus represented in YYYYMMDD form.