Unflatten JSON string truncates string with null character

Underneath the JKI JSON utility it uses LV flatten/unflatten from JSON primitive. Unfortunately, the unflatten from JSON primative has a bug that it truncates the input string when it hits null character.

Example:
```
{
"test":"\u0000\u0001\u0013"
}
```

This data after unflattened will retun empty string.