Add a dedicated endpoint to process payments.  Have the PaymentProcessor return better error messages (not done here quite yet)
Javadoc, moving GET Payment from `RegistrationResource` to `PaymentResource`
Adding functional test for new payment update endpoint
- altering initial DB build script to not have a "current" payment for the test conference.  in the new design the only payments that are ever stored are past payments
Rounding out payment endpoints, there's now GET, POST and PUT.
 - Functional tests work
 - Added javadoc
Merge pull request #80 from CruGlobal/client-only-creates-payments

Client only creates payments