msgpack v5

[hannesvdvreken]

There's a new kid in town:

https://github.com/mcollina/msgpack5

Here's one reason to switch:

creationix/msgpack-js@1e6feb3#commitcomment-8285013

[didaxRedux]

I agree!
I've also suggested a correction (see #105).
With old msgpack library errors occur on UInt64 conversion.

[darrachequesne]

Closed by #156.