Added a comment.
First cut at using maps to index extension objects.
Should iterate over outer classes when simplifying an equation between two instantiated types.
Applied the same fix to Sub/SuperConversionConstraint.
Added follow-up inference test cases.
Refactored class file reader to be independent of extensions, but to
rely on the major version number listed in the class file itself.

Merge remote-tracking branch 'origin/master' into NoDelFactory