Release of JDecisiontableLib 2.0.0

Today I can release JDecisiontableLib 2.0.0!

There are some changes which breaks API compatibility, therefore the new major version. Changes affect the API (easier to use/less confusing now) and the code quality but not the domain-specific algorithms. These remains unchanged!

A major change is the remove of the facility to serialise instances of JDecisiontableLib to JSON. Now, I consider it a mistake to add this facility in a library. Because of some fields changed their names compatibilty to release 1.3.1 would be broken. But I added some interfaces ("ISer.*") and factory methods to enable you to write an adapter to read data serialised that way. You may have a look at JDecisiontable 2.1.0 to see how it could be done.