- cleanup patch.py:
- make patch.py constructors more understandable
- loosen coupling of patch.py with package
- in Package: make package_dir, module, and namespace class properties
- These were previously instance properties and couldn't be called from
directives, e.g. in patch.create()
- make them class properties so that they can be used in class definition
- also add some instance properties to delegate to class properties so
that prior usage on Package objects still works