Used an adapted MethodGenerator to generate methods too for functions that have the object as the second arg after a first CFAllocatorRef arg (which we pass as NULL always anyway).

- Convert CFString to/from Python strings. Currently always MacRoman, to be fixed later (as is unicode support). Python->CFString conversion is automatic.

CFStrings are in better shape, but Unicode support and automatic conversion to/from Python strings remains to be done.

First small step towards bgen-generated CoreFoundation. there is hardly any real functionality yet, but method chains seem to work, and so do Retain/Release semantics.