Improve rethrow logic

[bopazyn]

I am thinking of introducing two new methods for ProblemDetailsOptions class:

• Rethrow<T>() where T:Exception
• Rethrow<T>(Func<HttpContext, Boolean> predicate) where T:Exception

The logic would run before ShouldRethrowException.

[khellang]

Hmm, in that case, I think we should just remove ShouldRethrowException altogether (it hasn't shipped yet) as it would allow you to misconfigure the middleware.

[bopazyn]

You are right. Having both would ShouldRethrowException and Rethrow would introduce many errors because the logic isn't obvious.

I can preapare PR in few days.

Edit: #88

[bopazyn]

PR was successfully merged into master.