fixed next being undefined instead of null (#101)
fixed next being undefined instead of null (#101)

Problem here is that if we call foreach() of values() function, isHeadOrTailLinkedDictionaryPair never returns true and we get a npe, because tail.next === null is always false. It is actually undefined. So a more general check fixes it.
basarat/typescript-collections,basarat/typescript-collections,basarat/typescript-collections