Refactor specs + fixes

- Cleanup + Refactor spec syntax (specs tend to be reused so why not
keep them well styled)
- Fixed Braintree a bit that had Test::Unit syntax in it, also
described pending tests
- Fixed SecurePayAU Gateway that had it active_merchant gateway
misspelled
- Fixed UsaEpay spec
- Add base classes for 11 gateways
- Updated read me and Versionfile
- Bumped dependencies