Take an Equivalence, not an Equality, for TypeChecked and ConversionChecked TripleEquals equality constraint methods.
Drop use of "Restricted" traits in tests.
Fixed a grammar error in contain matchers' error messages.
Changed all contain matchers that takes vararg to throw NotAllowedException when RHS is empty.
Changed contain matchers that takes vararg to throw NotAllowedException when values in RHS duplicates.