Stream: unpacking '0' doesn't trigger 'msg' emit 

msgpack.js: line 73, it should be `if (msg == null)`, instead of `if (!msg)` - if `msg` as unpacked correctly as `0`, would silent the 'msg' emission. Please fix.

ps: is this project dead already? if there is no maintainer anymore, please consider transferring the repo ownership, so the community can hopefully keep it alive. Thanks!