compile-only two argument "do-the-right-thing" tests verifies that all overload combinations compile without error

deprecated functions with enough signature or semantic changes that they are not supplied by default

name consistent with std containers

iterator_facade derived classes don't seem to like implementations in separate translation unit dll's, so forward to class path static members

std::lexicographical_compare would infinately recurse because path iterators yield paths, so provide a path aware version