Light.PortableResults 0.2.0

• Introduces Light.PortableResults.Validation which provides ValidationContext, Validator<T>, AsyncValidator<T> and a rich suite of assertions to simplify creation of errors.
• Write rich anti-corruption layers with Validator<TSource, TValidated> and AsyncValidator<TSource, TValidated>.

What's Changed

• Validation Foundations by @feO2x in #25
• Error Definitions by @feO2x in #27
• Child validator refactoring by @feO2x in #29
• Validation target redesign by @feO2x in #31
• Validation Checks by @feO2x in #33

Full Changelog: 0.1.0...0.2.0