Implemented msgpack::object_handle using the same design pattern as std::auto_ptr and std::auto_ptr_ref.
Minimized the uses of #if defined(MSGPACK_USE_CPP03) conditional macro.
Removed MSGPACK_API_VERSION_NAMESPACE(v1) from doxygen build.
It seems that Doxygen cannot parse a complicated macro such as MSGPACK_API_VERSION_NAMESPACE.
Added EXTRACT_ALL=YES to Doxyfle.
Added INPUT configuration variable that is point to include directory to Doxyfile.