[docs] reading multiple files means the minimum upper bound read is taken as the initial merged problem upper bound.

[error] correction in AMO generation: constructive disjunction is not compatible with variable elimination ; index of values in AMO graph should not change after creating vertices

[code] AddAMOConstraints also performs singleton consistency with constructive disjunction for free ; sorts vertices by conflict graph degree and current cliques by decreasing size when building a clique cover (to be improved by graph coloring heuristics like dsatur on the complementary graph)

small modification for VAC. Add arity sorting for linear constraint. Add objective consistency for AMO constraints. Perfom dynamic programming even when last optimal solution is optimal.

[code] INCOP local search takes into account knapsack constraints by relaxing the initial upper bound in order to minimize knapsack constraint violations