Removing cascading through inheritance chains for data formatters

This is the feature that allowed the user to have things like:

class Base { ... };
class Derived : public Base { ... };

and have formatters defined for Base work automatically for Derived.

This feature turned out to be too expensive since it requires completing types.

This patch takes care of removing cascading (other than typedefs chain cascading), updating the test suite accordingly, and adding required Cocoa class names to keep the AppKit formatters working

llvm-svn: 153272