Add disjunctive and minimum_except_0.

lib/minizinc/std/disjunctive.mzn:
lib/minizinc/std/minimum_except_0.mzn:
	Add the new constraints.

lib/minizinc/std/distribute.mzn:
	Fix up some formatting.

lib/minizinc/std/globals.mzn:
	Include the new constraints.