In cases where a working day either:
- Spans 24 hours
or
- ends at midnight
the time span calculation code incorrectly calculates the time of that
day, either stating that the day is 0 minutes long, or worse, is
negative.
The following patch addresses this. Non-working days are specified
using the Python 'None', or 'False' values, rather than specifying the
same start and end time, as the latter will now be interpreted as a
24-hour period.
bzr revid: me@vk4msl.yi.org-20120323052146-vosvz50lg12n7e1i