Add property based test
Fix https://github.com/scalatest/scalatest/issues/181 by using latest ScalaTest version
Fix invalid comparison between int and byte in packInt
add writeInt16/32 method to refactor integer output
Extract packXXX to MsgPackWriter
Encoding Map type
Encode map entries
working on map encode/decode
Add custom map pickler
Unpickle map type
Fix decodeLong