JLS writer creates invalid files

[mliberty1]

Version: 0.3.3
Platforms: All

Description

The JLS writer produces invalid data for null and empty (length 0) strings. Instead of valid UTF-8, we get something like this: b'8\xe9\x01\xd3\x01'.

Expected behavior

The JLS writer should serialize an empty string when provided with a null or empty string.

[mliberty1]

Added proper handling to both C and Python code. Fixed in 0.3.4 release.