Add 'support' for old-style classes by converting the new-style classes for now
Make the del statement work inside functions
'raise Exception' behaves the same as 'raise Exception()'

The python stdlib apparently uses a bunch of old-style ways
of doing things.

Instead of doing the throwing directly in the generated IR, call
a runtime function raise1 which will take care of the semantics
of checking the type of the raised object, etc.
Generate tracebacks correctly for 'raise' statements
Add sys.builtin_module_names

For os.py.  Currently just do it by inspecting the set of modules
at the end of the runtime setup; CPython does it by examining the
"import inittab".

Required adding str comparison methods so they can be sorted.

bonus: add errno module.
Handle bare 'raise' statements

Previously, a non-satisfied except filter would cause the traceback
to be lost, since we were using the one-argument 'raise exc' form.
Move the checksum to the beginning of the pyc

Now more resilient to truncated pyc files; got into a bad situation
where the parser crashed, wrote out a half-pyc file, which wasn't
judged to be invalid.
Make 'from a import b' throw ImportErrors

Before was throwing AttributeError, since we were just translating it to:
import a
b = a.b

Now there's a special importFrom runtime function that does essentially
the same thing, but throws the proper exception.
Oh, no this was the issue: we were writing out valid-looking but corrupt pyc files if the parser crashed.  Now leave the files as corrupt if the parser crashes
list.extend
implement delete attribute by reorganize hidden class
modify the procedure of looking up descriptor and add some comments