TPac; credit card payment "Processing..." page

TPac; credit card payment "Processing..." page

To prevent impatient patrons from re-submitting credit card payment
request forms, insert a Processing... page between the initial form
submission and the actual payment processing.

Steps 3-5 are new or modified.

1. User selects transactions to pay
2. User fills in payment form and Submits
3. Payment form data is cached in memcache with a temporary token
4. Processing page is displayed with message about how processing the
   payment can take time, do not refresh, etc.
5. Page is refreshed via http meta refresh to submit the form using
   the temp token.  The page is not visibly changed, though, since it
   takes time for the form submission to begin returning data.
6. User is directed to the payment results page.

Signed-off-by: Bill Erickson <berick@esilibrary.com>