Fixes #140 - issue with the 'capture' argument passable to https://strip...

...e.com/docs/api#create_charge. Currently being sent as 'captured' instead of 'capture'
Actually I think that line is fine. According to Stripe's docs it returns the data as a value named 'captured', just as django-stripe-payments stores it: https://stripe.com/docs/api/python#charge_object

Further more there's no mention of this property having changed in Stripe's API changelog.