Added Type#inheritedBy, to complement Type#inherits.
Improved the TypeDef abstraction. A.typeDef becomed a typeDef of type defs...
Added recursive creation functionality to A.create.
Major refactoring to types. Unified A.typeDef and A.type, into A.type.predicate (ptype) and A.type.complex (ctype), respectively, each descending from an "AbstractType" concept (atype).