Update description
Refactor lib/paypal.js
- Rename some variables
- Add comments to method 'remoteCall'
Add method to send a preapproval request
Implement actions /paypal/preapproval & /paypal/pay
Add a new method Paypal#createCommandLink
Response the paypal page link, to guide the client to finish payment or preapproval
Make tests passed
Refactor test/integration, extract a new module 'common'
Refactor controller Payment, to get the model class from a context object
Inject object 'paypalClient' in controller paypal
Refactor controller paypal, to move IPN verify method into lib/paypal
Add more tests for controller/paypal
Rename 'remote' to '_remote', to follow naming convention
Add test for lib/paypal
Add more tests for lib/paypal
Refactor lib/paypal, remove constant WebCommandPrefix & Endpoint