JSON String deserialisation of Datetime objects fails with Python 2.7

[Carina Haupt]

When with Python 2.7 a JSON String is deserialised in DataFinder, the Datetime object does not get deserialised. Reason is a hard coded False paramter in the DatetimeJsonDecoder which restricts the DatetimeObjectHook to not handle dictionaries. But the JSONDecoder which is called before the DatetimeJsonDecoder returns a dictionary. Therewith the Datetime objects are not handled.
The error is in /src/datafinder/persistence/metadata/value_mapping/json_format.py

This problem occurs for example when you use a SVN repository and try to look at the properties of a file using the context menu.