Remove usage of Object throughout repository

[iFergal]

In too many places in the repository, Object is used in place of actual types. Having to inspect the type and then Cast the object is error prone and doesn't make for a very nice library. With actual specified types it would be easier to use and document.

#53 covers removing Object from an API calls. The scope of this ticket is to remove the unnecessary use of Object elsewhere.

Note: There are some places where Object has to be used, because we are genuinely dealing with an interface that accepts some JSON structure that isn't known ahead of time.

However, there are other cases where code was ported from TypeScript but not handled correctly - for example:

    private void _processThold(Object thold) {
        if (thold instanceof Integer) {
            _processUnweighted((Integer) thold);
        } else {
            List<List<Fraction>> weightedThold = (List<List<Fraction>>) thold;
            _processWeighted(weightedThold);
        }
    }

For this, we can just use overloaded functions.

private void _processThold(Integer thold);
private void _processThold(List<List<Fraction>>) thold);