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]

libs/detail

@@ -1 +1 @@
-Subproject commit f9803293540ef55e40d77de15f150d1098d4fb31
+Subproject commit 092c5f5b52a6f1800ff645f31d5cb362e9debbb4

libs/iterator

@@ -1 +1 @@
-Subproject commit f325582c402211a56b88a66c5acc5ee0b0b70897
+Subproject commit bb7ac6bd84bfe62a5c8555979af028aa87babeb6

libs/type_traits

@@ -1 +1 @@
-Subproject commit d8914e583b4a9b9e4b990218eda1b342f04f8e29
+Subproject commit 42f271a4dc3f4bce7de8bb2154b19016d4b89cf9

libs/utility

@@ -1 +1 @@
-Subproject commit c86fcbf4567f7c5ceef9776fc108b1ca75864a9c
+Subproject commit b5ae0ad86ba60cc68598944baa54c776097b3cfd