User-Types not Being Instantiated when using CommandHandler.Create(MethodInfo method)

From #632 :

Even if the constructor requirement for user types is fully satisfied (i.e. it has a public constructor accepting just `string` as its only parameter), commands whose handler has been created via `CommandHandler.Create(MethodInfo method)`, or equivalently any other Func/Action-based overload thereof, do not still instantiate user types when those types are used as arguments, i.e.:

```
public static void CustomCommand(UserTypedArgument arg1, bool option1 = true) {
//UserTypedArgument is null here even if it has a public constructor accepting string that has been called
}
```

The constructors do get called, however the created instances are never passed onto the method, which receives them as nulls.