See Comments

* Added VCR cassettes for several client interactions, still a few to go
* Re-patterned all data Class specs
* Removed clean_hash as it is no longer needed
* Updated data Class constants according to BC code
* Updated data Class attributes according to BC code* Handle returned data with or without attribute prefixes in Base
* Refactored similar Client requests into a method
* Use BC example for encryption code.
* Add missing factories and use them in specs
* Update specs to near 100% coverage.
WIP: Further

* 3 failing specs remain
* Still need to test the several transaction types (auth, capture, sale, etc.)
Fix failing specs
Fixed some rubocop issues
Add 2 new classes

* Add PushNotification
* Add SettlementBatch
README updates, cleanup