Added initial billing API, hacked into top of BaseSpaceAPI object
Split BaseSpaceAPI.py into separate files for base-class BaseAPI and children BaseSpaceAPI and BillingAPI
Bug fix: removed PurchaseType from models/ init
Added TODO to add exception logic for getAppSession()
Added invoice number to Purchase model
Now catching HTTP Errors on urllib2 urlopen request to be able to parse BaseSpace error msgs in response content -- prev was only getting HTTP error code in exception, which wasn't informative enough
Updated Purchase API to support new fields including RefundStatus, Product PersistenceStatus, compact Application and AppSession, provide AppSessionId during POSTs, and new Exception messages
Added billing method getUserProducts() for API method GET:users/current/products
Added refundPurchase() and example script that creates a purchase and refunds it
Fixed token bug for refunds
Forgot to add RefundPurchaseResponse to commit
Added checking status of purchase after returning from BaseSpace