This change improves typing support throughout Spina, helping to cement some patterns, improve code maintenance, and correct typing issues in derived classes. `SpinaClass` is now a generic `SpinaClass<TBase>`, which takes in the class being typed, merges with it, and sets the prototype to it. This replaces the `SpinaClass & TBase` we had internally in several places, and gives us a proper up-front type to avoid some casting. Untyped, it behaves like it did before. `__super__` is now mapped to `any` instead of `object`, avoiding type errors when looking for attributes/functions on parents. Backbone's `_Result<T>` is now exported in Spina as `Result<T>`, giving us a non-private, stable type we can use when we need to reference a type or callable returning the type.