Equivalent to B #= (Con), Bool #= 1-B
Bool is the logical negation of the reified truth constraint Con. Con must be a constraint that has a corresponding reified form.
ConsistencyModule is the optional module specification to give the consistency level for the propagation for this constraint: gfd_bc for bounds consistency, and gfd_gac for domain (generalised arc) consistency.This constraint is implemented using Gecode's MiniModel's rel() for both integer and boolean expressions, with sub-expressions/constraints not supported by MiniModel factored out and posted as auxiliary constraints.