Thanks to Info-ZIP for info on the DOS-time/date conversion code,
and some other general information gathered from their sources.

Thanks to these people for suggestions, testing, and bug reports:

Alexander Galanin <al@galanin.nnov.ru>
Heiko Hund <heiko@ist.eigentlich.net>
Joel Ebrahimi <joel.ebrahimi@gmail.com>
Pierre Joye <pierre.php@gmail.com>
Roberto Tirabassi <rtirabassi@3di.it>
Simon Talbot <simont@nse.co.uk>
Stephen Bryant <steve@bawue.de>