Yes, now that there's two, it might be better to make them module globals.  @siyuz, could you move both `got_kbdint` and `sigint_timer` to being scalar module globals? Just assign them to `None` in a well-marked block at the top, and use the keyword `global` inside the function.

That's a good balance between asking for a full class refactoring and at least removing this ugly hack.

@siyuz, once that's done I'll gladly merge this. Thanks for your patience with the review process!