generic tests for standard conforming iterators

svn path=/branches/iterator-adaptors/boost/boost/iterator_tests.hpp; revision=7650
added transform_iterator, indirect_iterator, reverse_iterator, integer_range

svn path=/branches/iterator-adaptors/boost/boost/iterator_adaptors.hpp; revision=7652
fixed g++ operator ambiguity problem bu adding iterator_comparisons class

svn path=/branches/iterator-adaptors/boost/boost/iterator_adaptors.hpp; revision=7653
Simplified things a little by removing an unused template parameter from
iterator_comparisons<>. Conditionalized the use of iterator_comparisons<> on
BOOST_RELOPS_AMBIGUITY_BUG.

svn path=/branches/iterator-adaptors/boost/boost/iterator_adaptors.hpp; revision=7666
Some fixes for MSVC6, plus changed instances of BOOST_NO_ITERATOR_TRAITS to
BOOST_NO_STD_ITERATOR_TRAITS.

svn path=/branches/iterator-adaptors/boost/boost/iterator_adaptors.hpp; revision=7669