Message2383

This patch (made against 2.1 final) fixes two problems:

1. When importing from a jar/zip on the PYTHONPATH,
"import foo" will now load foo$py.class from the jar.
Previously foo.py would also have to be present in the
jar, or else foo$py.class would be ignored. Of course
if foo.py is present and newer, that will still be
preferred.

2. As a last resort, "import foo" will use
Py.findClassEx to load a class called "foo$py".
Previously there was no obvious way to load a python
module from the current classpath, unless it had been
compiled to have the name "foo$Py_Inner" (perhaps
Jythonc does it this way, I don't know).