Iterator

Implementation of an iterator that goes thru a Component and all its sub-components in a tree (pre-order) traversal. A test case that demonstrates the usage is also included, along with wrapping to make these iterators accessible from scripting..
Needs a period. Also, it is not adding anything as-is since it is obvious that's a default constructor. I would say something like "Default constructor does nothing; for use by derived classes only." or whatever. In fact should this be protected?