Various tweaks to displaying payments
 - Payments are now fetched by a direct call to the Payments endpoint (via $http) instead of using a cache
   - I'm not sure if this is ideal or not, feedback welcome
 - When creating a payment, paymentType 'CREDIT_CARD' is required for processing a CC payment
 - Adding paymentType to paymentsModal
 - Changing label "Transaction" -> "Reference #" in paymentsModal.
   - This could probably use a tooltip for more information