Check for msgpack version and switch bin packing
Check for msgpack version and switch bin packing

msgpack version > 1.0 changes the API for raw byte data to use
`msgpack_pack_bin` function instead of `msgpack_pack_raw` which was the
function to be used for earlier versions. We check the
`MSGPACK_VERSION_MAJOR` constant value and switch the function accordingly.

code-mancers/rbkit,code-mancers/rbkit,code-mancers/rbkit