Cleaner date adjustment using calendarOffset.  Refs #9533, #9300, #9042, #9515.
Cleaner date adjustment using calendarOffset.  Refs #9533, #9300, #9042, #9515.

Scheduler used to assume work week.  Now let calendarOffset() do that.

Also, it seems rounding errors would creep in and some datetimes would
have non-zero microseconds.  This tests for beginning and end of day
with a little delta.

git-svn-id: 2159781fc7c14c6bdd1f7e265daf7a25099c31e7@11079 7322e99d-02ea-0310-aa39-e9a107903beb

trac-hacks/trac-jsGantt,trac-hacks/trac-jsGantt,trac-hacks/trac-jsGantt