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]

test/Jamfile

@@ -29,6 +29,7 @@ test-suite iterator
     # These tests should work for just about everything.
     [ compile is_lvalue_iterator.cpp ]
     [ compile is_readable_iterator.cpp ]
+    [ compile pointee.cpp ]
       
     [ run unit_tests.cpp ]
     [ run concept_tests.cpp ]