RSVP: Shirts: Make payment easier

Add a Paypal button to the shirts order form,
and update everything for the 2014 event.
Fix: Admin: Shirt summary, use guest data

We weren't using any data when trying to calculate
the shirt-order summary.

Also, the callback when sending shirt emails was broken.
RSVP: Bump version on shirt pages

We're sometimes hitting the cache from last year
with the shirt pages, so change the filenames.
RSVP: Shirts: Remove 'now printing' text

The shirts aren't being currently printed, so
remove the text that says so.
Fix: Admin: Shirts: Use shirt data, not surveys

Typo in the data refresh stuff on the shirts panel.
Admin: Filter shirt style names for 2014

Use a simple filter to convert our shirt data
into a report that makes sense in the 2014 context.
RSVP: Note who picked a shirt during rsvp

We only want to send emails to people who weren't
given the opportunity to choose a shirt during
the registration process, so add something like
that to the data model.
Contact: Add Facebook event link
Admin: Log errors on payment page
Contact: Add link to payment page