Next commits will provide config object from callsides. The config
object is currently empty.
The config object is passed to all children mutators. Currently no
mutator public interface was modified so no spec changes. With next
commits we have public visible stuff so specs will be adjusted.
* Change util mutators to hide themselves from the context parent chain
this allows to use parent_type helpers in all node mutators
* This is the OO API feature fix for #10. CLI flags are still missing.