Adding invoice_description specs
2.2.1
Merge pull request #77 from recurly/coupon-invoice-description

Adding invoice_description specs
Adding preview to subscriptions
Merge pull request #78 from recurly/sub_previews

Adding preview to subscriptions
Bump version
remove recurly.js v2 references in readme doc
Merge pull request #80 from recurly/readme-edit

remove recurly.js v2 references in readme doc
add remaining billing cycles to the subscription