Jobs: .With() extension methods.

[ig-sinicyn]

As requested by @adamsitnik

Changelist:

• Jobs: WithXxx() extension methods added back, docs updated.
• Jobs, minor bug fixed: Id was cleared on explicit JobMode assignment + test for it (Test03IdDoesNotFlow).
• Jobs.Accuracy, typo: AnaylyzeLaunchVariance => AnalyzeLaunchVariance, docs updated.

[AndreyAkinshin]

In the original design, the WithXXX() methods don't change the original job, it always creates a copy of the original job with requested change. Could we keep this approach?

[ig-sinicyn]

@AndreyAkinshin yep, I've think about that, but it feels very counterintuitive.

There're mutable properties, there's .Apply() method that updates the instance of the job and there're .With() methods that create a new copy of the Job on each call. Kinda Js/PHP style : )

I'd prefer to keep standard Create-Init-Freeze-Reuse approach until there're strong reasons against it.

[AndreyAkinshin]

Ok, let's consider the following situation: I want to have a dry job for Mono. Before the refactoring, I could take the predefined Dry job and create a DryMono job in the following way: Job.Dry.With(Runtime.Mono). It was the main use-case of the WithXXX() methods.

[ig-sinicyn]

@AndreyAkinshin

Ok, I've fixed the .With() method logic. Should not break compatibility now.

[ig-sinicyn]

Oops, last minute fix had broken smth. Fixed