Simplify class Interval

[merkste]

By making Interval generic, the code is simplified.

Please note that restricting the generic type to <T extends Number>
is not possible yet, as this breaks code dealing with type Object only.

[davexparker]

In another branch, I have a new generic Interval class, but created in the common package. My plan was to migrate to that where used, and then deprecate this one later.

Btw, what's the missing text above "restricting the generic type to..."?

[merkste]

common.iterable also contains a class Interval. It is quite similar to RangeIntIterable. In the context of #57 I am about to integrate both into one class to get rid of the duplication.

[merkste]

Btw, what's the missing text above "restricting the generic type to..."?

This ist just GitHub stripping everything between angle brackets. In this case < T extends Number>.