Separate out set_up_service from get_authorize_url.
Separate out set_up_service from get_authorize_url.

Functionality should be separate for the two, but get_authorize_url sets up a service if there isn't one already

Brought up because of issue #8

ferdiaz/python-quickbooks,porn/python-quickbooks,emburse/python-quickbooks,troolee/quickbooks-python,sidecars/python-quickbooks,ZachGoldberg/python-quickbooks