Consider adding while loop constructor for results

[JohannesMoersch]

Not sure what the best syntax would be, but some ability to continue looping on a predicate and automatically exit if there is a failure result would be valuable. Not sure if this would be a static method, an extension, or both.

[JohannesMoersch]

Might making writing a result aware aggregate much easier as well.

[RyanMarcotte]

Is this different from this scenario: https://github.com/JohannesMoersch/Functional/blob/master/doc/advanced-scenarios.md#aggregation-of-resulttsuccess-tfailure ?

[JohannesMoersch]

The case I had in mind is for a scenario where you want it to loop forever until there is a failure or an exit condition is met, but the case you specified is definitely related and is also worth addressing. It feels like a special case of the loop forever scenario (with an input value for each iteration and an implicit exit condition at the end of the source enumerable).

[JohannesMoersch]

Closed #26 since these are related.