20191123
New features:
- Reified global constraints (requires at least MiniZinc 2.3)
- bool2costs allows to turn Boolean MiniZinc expressions into soft constraints (see README)
Bug fixes:
- Handle overflows in propagation of linear constraints
- Fixed cumulative to ignore tasks with negative duration or consumption
- Fixed diffn to ignore rectangles with negative width or height
- Fixed disjunctive to ignore tasks with negative duration