Similar to task macros, the parsed value is accessed by calling `parsed`
on a Parser[T], Initialize[Parser[T]], or Initialize[State => Parser[T]].
Values of tasks and settings may be accessed as usual via `value`.
In order to correctly pattern match Tree subclasses in reflection/macros,
scalac needs the corresponding implicit for *Tag available because the types
are only abstract types.
That is, implement Initialize[Task[T]].flatten correctly.
This requires preserving the transformations applied in a scope so that
they can be applied to an Initialize value after static settings have been
evaluated.
* use normal TypeTree constructor
* remove unnecessary 'with Singleton' in macro utility
* integrate changes suggested by @xeno-by
* add refVar back and call asTypeConstructor instead of asType to refer to a type variable
Mark Harrah