In timezones where daylight savings time is used, courses that start
on a Monday at 00:00 would display the week headings incorrectly
during the change forward.
When the time changes backwards, courses that have a start time of
Sunday at 23:00 also have a mislabeled week.
This attempts to use the DateTime() library, along with the user's
local timezone setting to display the correct day, rather than just
subtracting 86400.
Marty
b2eff97b64