make a tuple for bases even when the only base is object.
Quick fix for list.__setitem__
Final solution depends on the address issue settlement
regression for __setitem__ mutation on lists
Some cleanup of cascade

Name the type of interp-cascade, and avoid list-tests/filters to find abnormal
returns.
Change bases in CClass from (listof symbol) to CExpr
Add helper function builtin-class in util.rkt and change CClass
for builtin-class in builtin classes written in core language.
Add regression test for the bases scoping bug fixed in previous commit
This one: f26bc4180b3e317c8890c3bb51d9b24b751aba8c
Moved passing tests in tests/bugs to tests/python-reference for regression testing
Change tests/bugs/address-of-none.py since it was reversed
these lines were unnecessary
Merge branch 'master' of github.com:brownplt/lambda-py
redex: update core to match python-core again, update / fix tests, simplify testing macro
Merge branch 'master' of github.com:brownplt/lambda-py
Fixed isinstance to work with tuples of types, it is on isinstance.py now.
Added %isinstance and %iter bindings and changed desugar to use them.
Merge branch 'master' of https://github.com/brownplt/lambda-py
Removed isinstance builtin, did some cleanup and add regression test
Includes moving next() to pylib/seq_iter.py and removal of the unused iter_lambda
Added $object binding and used it to desugar bases
merge brownplt/master into modules-rewrite