Some changes in class hierarchies etc.; transforms no longer has a common
base class and VisitorTransform is a subclass of TreeVisitor rather than
the reverse. Also removed visitor use of get_child_accessors;
child_attrs is accessed directly (because of claims of overengineering :-) ).

--HG--
rename : Cython/Compiler/Transform.py => Cython/Compiler/Visitor.py