Creates the NullIterator implementation of the IIterator interface.

Adds a NullIterator implementation of the IIterator interface which enables the creation of classes that cannot be iterated in a hierarchy of class that can be iterable.

More details about the NullObject design pattern:
http://en.wikipedia.org/wiki/Null_object

Note that this implementation can easily be tested given the lack of logic in this new class. Unfortunately, I am not familiar at all with your (own?) test framework and the test has to be written.