No warning for derived methods that are not marked "override" or "new"

[Chuck]

For example, if you define:

    def equals(other as Object) as bool
        ...

Cobra will not warn that .equals is not marked as "override" or "new" and not invoking base. This is particularly bad for .equals because the custom method will not get invoked for expressions like "a == b". This becomes a silent bug at run-time.

[Chuck]

This was only a problem when the derived method parameter types were different by being nilable or not.

Fixed in changeset:1745