Fix the tests and implement a fake stripe.

app.py

@@ -1,6 +1,5 @@
 import logging
 import os
-import stripe
 
 from flask import Flask
 from flask.ext.principal import Principal
@@ -12,6 +11,7 @@ import features
 from storage import Storage
 from data.userfiles import Userfiles
 from util.analytics import Analytics
+from data.billing import Billing
 
 
 OVERRIDE_CONFIG_FILENAME = 'conf/stack/config.py'
@@ -43,5 +43,4 @@ mail = Mail(app)
 storage = Storage(app)
 userfiles = Userfiles(app)
 analytics = Analytics(app)
-
-stripe.api_key = app.config.get('STRIPE_SECRET_KEY', None)
+billing = Billing(app)