add config macro BOOST_NO_CXX11_RVALUE_REFERENCES_FOR_THIS

[akrzemi1]

Add another macro for detecting the feature known as "rvalue references for *this" (​http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2439.htm). I need it to implement features in Boost.Optional.

According to online references, it is implemented in:

• Clang 2.9 (​http://clang.llvm.org/cxx_status.html)
• GCC 4.8.1 (​https://gcc.gnu.org/projects/cxx0x.html)
• Intel 14.0 (​https://software.intel.com/en-us/articles/c0x-features-supported-by-intel-c-compiler)
• not in VC++ (​http://msdn.microsoft.com/en-us/library/hh567368.aspx)

[John Maddock]

This is BOOST_NO_CXX11_REF_QUALIFIERS