- Implemented info report.
- Removed odd Subst and Sequence objects from Task - are they just
vestigial limbs, or did I add them for a good reason? They are
gone now.
- Added Filter::applySequence to replace old filterSequence.
- Removed obsolete report.cpp filter function.
- Converted active, overdue and completed reports to custom reports.
- Added new recurring report.
- Added support for new 'end' column, which is the completion date.
- Renamed parse.cpp -> valid.cpp to reflect its new role of housing
all the validation routines that don't belong to objects.
- Split report.cpp into report.cpp and custom.cpp.
