setup: require stripe>=1.7.4 (instead of ==)
authorize.net: enable live test mode

For details please see:
http://developer.authorize.net/guides/AIM/wwhelp/wwhimpl/common/html/wwhelp.htm#context=AIM&file=5_TestTrans.html
Merge pull request #17 from tomscytale/master

Trying to pull all forks into main