Add method aliases for customer, transactions and payment methods
Alignment in README.md
Merge branch 'adding-test-coverage' of https://github.com/sosedoff/arrow_payments into adding-test-coverage

Conflicts:
	README.md
Merge branch 'master' into adding-test-coverage
Tweak some alignment.
Use stub_api helper in customers spec.
Remove trailing whitespace and tweak some alignment.