API Version 2.9

[bhelx]

This PR contains the changes needed to bump to API version 2.9.

1. Adding the authorize endpoint for Purchases. You can read about authorize in the dev docs. Example:

$purchase = new Recurly_Purchase();
$purchase->currency = 'USD';
$purchase->collection_method = 'automatic';
$purchase->account = new Recurly_Account();
// In this case, email is required
$purchase->account->email = 'benjamin.dumonde@example.com';
$purchase->account->account_code = 'aa61-4790-8e61-0a2692435fee';
$purchase->account->first_name = "Benjamin";
$purchase->account->last_name = "Du Monde";
$purchase->account->address->phone = "555-555-5555";
$purchase->account->address->email = "verena@example.com";
$purchase->account->address->address1 = "123 Main St.";
$purchase->account->address->city = "San Francisco";
$purchase->account->address->state = "CA";
$purchase->account->address->zip = "94110";
$purchase->account->address->country = "US";

$billing_info = new Recurly_BillingInfo();
$billing_info->number = '4111-1111-1111-1111';
$billing_info->month = 12;
$billing_info->year = 2019;
$billing_info->verification_value = '123';
$billing_info->address1 = '400 Alabama St';
$billing_info->city = 'San Francisco';
$billing_info->state = 'CA';
$billing_info->country = 'US';
$billing_info->zip = '94110';
// Tells Recurly that an external payment collection method will be used.
// In this case, Adyen HPP.
$billing_info->external_hpp_type = 'adyen';

$purchase->account->billing_info = $billing_info;

$adjustment = new Recurly_Adjustment();
$adjustment->unit_amount_in_cents = 1000;
$adjustment->quantity = 1;

$purchase->adjustments = array($adjustment);

$subscription = new Recurly_Subscription();
$subscription->plan_code = 'gold1';

try {
  $authorized_invoice = Recurly_Purchase::authorize($purchase);
  print($authorized_invoice);
} catch (Recurly_ValidationError $e) {
  print($e);
} catch (Recurly_Error $e) {
  print($e);
}

2. Not a code change, but the subscription link on an instance of Recurly_Adjustment is now only created if adjustment is originating from a subscription plan charge, setup fee, add on, trial or proration credit. It is no longer created for other adjustments.

3. Also not a code change, but instances of Recurly_Transaction and Recurly_Invoice no longer have a subscription link and you must now use the subscriptions link.

[drewish]

Looks good