Update plan and pricing required for Chargify Direct
Adding documentation for product input attributes
Merge pull request #16 from lukerattei/patch-1

Update plan and pricing required for Chargify Direct
Add trial_ended to subscription states
Fix links, add vat_number to customer api documentation
Add direction documentation to events api
Only owners can, not admin users
Merge pull request #17 from ryansch/product-input-attributes

Adding documentation for product input attributes
fixes #8
Fixes #9, adding blurb to product archiving
Changing back from CRLF to LF line-endings
Added description of the "preserve_balance" flag on reactivations
Many improvements to Webhooks documentation

* Indicated that the `id` parameter is a part of all webhooks
* Added section on "Webhook Acknowledgement and Automatic Retries"
* Added section on "Webhook Metadat"
* Added examples of every kind of Payload
Added anchor for Webhooks Retries section
Added clarification for webhook attributes
Webhook metadata updates missed in last commit
Restored LF line endings
Add `direction` parameter description to customers listing
nonce is a required parameter now
add shipping address information to subscriptions api doc under customer_attributes