Updating wrong date in license header
A bit of defensive programming
Adding ability to manipulate the Internal JsonObject.

This is an "experimental" API and should be used wisely.
Changing anything on that has immediate effect on
the containing JSONConf object.

Fixes #5.
The number of User Config JSON files is now arbitrary.

Any number can be provided.
Order defines the way the UNION will be applied.

Fixes #4.