MSVC 2013 type trait support

Implement type trait primitives used in the latest edition of the Microsoft
standard C++ library type_traits header.

With this change we can parse much of the Visual Studio 2013 standard headers,
particularly anything that includes <type_traits>.

Fully implemented, available in all language modes:

 * __is_constructible()
 * __is_nothrow_constructible()
 * __is_nothrow_assignable()

Partially implemented, semantic analysis WIP, available as MS extensions:

 * __is_destructible()
 * __is_nothrow_destructible()