Added `nonlocal`. `global` takes multiple args.

Related to https://github.com/hylang/hy/issues/246
Looks like `unittest2` and `@unittest.skipUnless(PY3, "Requires python 3")` should work in theory with nose and all pythons. But in practice I'm having troubles getting it to work.

https://pypi.python.org/pypi/unittest2