added wchb test case for local rules
implement Rule::edit_property and corresponding prsim command
split up min-delay contraint by direction [2][2]
improve min-delay diagnostic verbosity
support per-direction min-delay constraints
restructure min-delay constraints into 2x2 arrays of time/predicate
to represent unate-ness and directionality of constraints
printing order slightly shuffled as a result of this change