Moved to much cleaner system of using BOOST_TT_BROKEN_COMPILER_SPEC

for handling vc6/7 deficiencies with iterator_traits.

Fixed a bug in iterator_facade which was causing incomplete types to
be passed through is_convertible.

Reinstated libs/utility/iterator_traits_test.cpp


[SVN r19840]

counting_iterator_example.cpp

@@ -12,22 +12,6 @@
 #include <boost/iterator/counting_iterator.hpp>
 #include <boost/iterator/indirect_iterator.hpp>
 
-#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
-namespace boost { namespace detail
-{
-  template <>
-  struct iterator_traits<int*>
-      : ptr_iter_traits<int>
-  {
-  };
-  
-  template <>
-  struct iterator_traits<int**>
-      : ptr_iter_traits<int*>
-  {
-  };
-}}
-#endif
 int main(int, char*[])
 {
   // Example of using counting_iterator_generator