Fix return type in metafunction document

Signed-off-by: Kohei Takahashi <flast@flast.jp>
Merge pull request #8 from Flast/pr/doc/metafun

Fix return type in metafunction documentation
Ticket 9851 - adaptors should perform concept check assertions.
any_iterator now compiles without RTTI.
change to fix MSVC 8 unit test failure due to uint32_t.
Update any_range.qbk

Fix typo in the name of forward traversal tag.
Merge pull request #9 from romanek-adam/patch-1

[doc] Fix typo in the name of forward traversal tag.
add Enabler template argument to range_iterator, range_const_iterator and range_mutable_iterator extension points.
allow clang to use Range Concepts despite reporting GCC 4.2.
remove crazy execute file attribute from header files.
changed the separated function to become the new formatted adaptor.
bring formatted_range into the boost::range namespace.
add a range_fwd.hpp header file for the main classes/structs and the extension points.
trac_10098 iterator_range sign warning.
change the return type from the indexed adaptor so that the index is available from the range element.
Replaced deprecated cast.hpp with polymorphic_cast.hpp. Droped dependency to the Numeric library
more robust implementation for BOOST_RANGE_EXTRACT_OPTIONAL_TYPE
Merge pull request #10 from apolukhin/develop

Replaced deprecated cast.hpp with polymorphic_cast.hpp. Droped dependenc...
fixed and resolved missing coverage in the copy_backward unit test.
More remove execute attribute from files.

  rel. to:
  https://github.com/boostorg/range/commit/e0e6fefb1ed5e6207428143876f507d45b381891

Signed-off-by: Kohei Takahashi <flast@flast.jp>