Preliminary work on getting paypal integrated
Makes Payment an STI class

We now have ManualPayment and allows for PaypalPayment
Adds add_host_paypal_account rake task
Paypal IPN handling
Adds logging for GATEWAY.setup_purchase
Adds PayPal specific information to payment table
Redirect to tournament registration page
Adds PayPal request specs
Implements paypal completed and canceled handling
Payment table redone

Adds a separate table for Paypal and ManualPayments
Redo the table columns for Manual and Paypal payments
Extract the gateway stub to a separate file
Adds paypal completed page