Display banner notification about impending credit card expiration. Resolves #2211
Added caching requests to Balanced
we don't want to call participant.get_tips_and_total() when running pachinko
filter takes we've already processed
add a comment
add mappings to StripeCard for expiration attributes

https://stripe.com/docs/api/python#cards
make quotes style consistent
fix type of `NOTIFIED_ABOUT_EXPIRATION`
Merge pull request #2379 from gittip/expiration-banner

Display banner notification about credit card expiration
Bump version to 12.11.1
Bump version to 12.11.1-dev
Note Perl API client (and reformat for 80 chars)
Use canonical link for Perl module
Refactor the fix for duplicate pachinko transfers

 - Add a for_payday parameter to get_current_takes, on the pattern of
   Participant.get_tips_and_total. I believe this adequately reproduces
   the semantics of the inline takes query currently on the fix-payday
   branch.

 - Teach genparticipants about the different loops, harmonizing the
   semantics of that generator in the various loop cases. Now it knits
   in different extra info based on the loop: tips and total for
   payin/payout, takes for pachinko.

My goal here is to provide a consistent implementation of the several
payday loops.
propagate elsewhere.is_team to participants.number
create GitHub.is_team_admin()
implement connecting elsewhere team accounts
allow pledge/lock/unlock for elsewhere team accounts
prevent connecting a team account without having another account to log in
move the list of team members to the bottom of the page