Overload methods with named parameters

[mjallday]

It's much easier to use these libraries when the IDE can tell you the name of the parameters it accepts.

e.g. https://github.com/balanced/balanced-csharp/blob/master/Balanced/Card.cs#L103

public override Debit Debit(Dictionary<string, object> payload) {}

may be complemented with

public override Debit Debit(Int amount, String description, Dictionary<string, object> extras) {}