Added traits:

   is_incrementable.hpp: checks whether ++x is well-formed

   pointee.hpp: value_type of iterators or smart pointers

   indirect_reference.hpp: reference type of iterators or smart pointers

indirect_iterator.hpp
indirect_iterator_member_types.cpp

   Use pointee/indirect_reference to select value/reference type.

iterator_concepts.hpp: Fixed interoperable test.  Hardly tests enough, but it's a start

minimum_category.hpp: Better error messages for vc6

indirect_iterator_test.cpp: Workarounds for compilers without SFINAE

static_assert_same.hpp: Informative error reports; added a macro.

zip_iterator_test.hpp: Added missing #include

Jamfile: made zip_iterator test pass with vc6/stlport

[SVN r21514]
Updated pointee and indirect_reference so that pointee represents the immutability of the pointed-to type via const qualification. The pointee of a proxy-based iterator will be const qualified unless a mutable reference to the value_type can be bound to the returned proxy.

Added a test for pointee

Fixed iterator_facade so operator[] result type computation didn't
cause a problem with abstract types.

Updated iterator_facade operator[] docs for accuracy.

Allowed Borland to simply fail the indirect_iterator_member_types test
because of its lame const-dropping, instead of trying to work around
it.

[SVN r21579]
Kill off outer cv-stripping of Dereferenceable

[SVN r21696]
merge new MPL version from 'mplbook' branch

[SVN r24874]
Link to documentation added.

[SVN r27745]
Removed executable attribute.