Xam.Settings: consider transparent json serialization

[nirinchev]

On iOS if I try to persist a non-value type, there's an exception thrown in the default case. Is there a reason we can't use Json.NET to serialize to/from string? I know it's kind of encouraging bad design, but still, would be useful in some cases.

[jamesmontemagno]

You are able to do this manually, however I do not support this in the current implementation and have no plans on it at this time.