Remove utf8 encodeing in JSONCodec
Taurus JSONCodec apart from JSON serialization encodes and decodes using "utf-8". This in python 2 means that the API is based on strings and in python 3 it is based on bytes.
In pure Python however json.dumps and json.loads works on strings for both python 2 and 3.
Adapt Taurus JSONCodec to have the same behaviour than pure Python library.
Solve #945 (closed)