Defines a set of permitted mappings from [interface] Class objects to
Implementation factories that can generate instances of the facet represented
by the Class.
author: Jeremy Carroll (original code)
newInstance(Class interf, Node n, Polymorphic that) make a new instance of a type _interf_ based on the node _n_ and the
polymorphic _that_; use the implementation wrapper for _interf_ in
_types_.
Add a new interface and its implementation to this Personality.
Parameters: interf - The interface to add, expressed as a Type object. Parameters: impl - A way of implementing _interf_.