Membership confirmation using cycles

[adehnert]

I think each time we do a membership confirmation cycle, we want it to be a cycle --- each group needs to confirm during that cycle. We should assign both group and people's submissions to a cycle, and enforce that you can submit at most once per cycle (and later submissions modify earlier ones).

Conveniently, fixing this will probably naturally make the ​status page not full of lies.

[adehnert]

Half-fixed --- people are in cycles, but groups still aren't. This means that the status page works, at least.

[adehnert]

Fixed in:

commit 742e9c0b449fe1bb7f2d3a9d50a606ac0a0efd4e
Author: Alex Dehnert <adehnert@mit.edu>
Date:   Sun Nov 4 01:13:13 2012 -0500

    Finish support for group membership update cycles
    
    The revised workflow is that you visit a group selection page, and select a
    group to update. That checks authz (ASA-#169) and then loads any old update in
    the appropriate cycle (ASA-#27).

[adehnert]

Whoops, new hash: bda4d865e3f659470094cfdd2bebea96f326fe53