Several small changes.  Mostly reformatting, adding parens.
Several small changes.  Mostly reformatting, adding parens.

Check for free in class and method only if nested scopes are enabled.

Add assertion to verify that no free variables occur when nested
scopes are disabled.

XXX When should nested scopes by made non-optional on the trunk?

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator