MiniZinc: added 3sum.mzn, minsum.mzn, power_set3.mzn, and timetable.mzn
Picat: added 3sum.pi, minsum.pi, penguin.pi, rogo2.pi, and timetable.pi
Picat: added 3sum.pi, minsum.pi, penguin.pi, rogo2.pi, and timetable.pi