A single page payment form

Provides a single page payment page where a user can enter payment information and an amount to pay.
Good for donations, settling invoices for services not managed by the current commerce system.
Provides an order with transactions against it much like a normal checkout process.
Provides a couple of alter hooks so additional form fields can be easily processed along with the order.
If you want to add an invoice reference field or a notes field, simply add that field to the order entity and it will show up on the form.
Notes from README.txt:

Only supports a single payment method at a time (but you could alter which method to use using provided hooks)
Requires a product be set up as the base product of the transaction. This is done automatically when you first access the payment form (if you have the proper permission)
requires the default setup for drupal commerce such that entity relationships exist like this:
The default product type "product" must exist
**Depends on most of the commerce modules**
1. Install module
2. The form will work at /justpay
3. There is also a Commerce Justpay block which you can set up to show the payment form wherever you like
4. Use commerce rules to configure what happens after payment, by default you just get returned to the form.
5. Configure the product dummy JUSTPAYMENT sku to set the currency of the payment

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