Clean up IL generation.

Add an extra helper for local arrays and fix some subtle issues with IL generation.
Add test harness for typed classes.
Remove the accessor static properties, as they don't make sense from Python.

Hopefully there's a way to make them work, but I'm not sure what yet. Python
properties depend on the descriptor protocol, which only works off for
instances, not types.
Fill out the typed_class test cases.
Properly name the 'value' parameter to setters.
Fix a typo in typed_class.py.