handle: A Range that handles an Exception

When a Exception occurs inside a range chaining the whole chain dies usually. The Handle range fixes that, as it catches a defined exception and calls an user defined handler on it.
I don't like that idea so much as it makes the range somewhat eager and depending on the Input consuming it completely. In the constructor I would have to call popFront and if that fails it would have to repeat the loop, maybe even until IRange is empty. 

I, as a user, would be surprised if the computation would happen inside the creation of the range not at its use.