Add a clean_agrees_to_tos() validator that requires "Yes" if ToS exists.
Also, more user_logic.logic => user_logic fixes. If you are going to import
"as", you might as well make the renaming worthwhile. Maybe we need to add
a section on "import ... from ... as ..." in the style guide?
Patch by: Todd Larsen
Review by: to-be-reviewed
Benjamin Niemann <pink at odahoda dot de>: Main developer of Python target.
Clinton Roy <clinton.roy at gmail dot com>: AST templates and runtime.