Add solution id

[hillelcoren]

This changes enables setting the solution id

http://developer.authorize.net/api/solution_id

Solution ID enables software vendors to uniquely track the transactions submitted from their application to Authorize.Net.

Unlike your merchant referrals, which are tied only to your Affiliate ID, Solution ID identifies the application creating a transaction for every merchant using your software regardless of who sold the application, gateway or merchant account.

[judgej]

I've removed PHP 5.3 from the travis builds. If you pull from master into your branch, you should be able to get through the tests.

[judgej]

I'll try and get a few PRs fed through over the coming week. Just busy fighting with Datatables today...

Can I confirm that this change is working for you in production? Authorize.Net can be a little more fussy about the order of the XML fields in production than it is in test instances.

[hillelcoren]

Ok, no rush. I'm using a custom fork in the meantime. I've tested this on my development machine, it'll be in production in about 6 weeks.

It took me a little while to get it working due to XML errors from the fields being out of order but it's now working correctly.

[judgej]

It's pretty poorly documented - I couldn't find the solution ID in any of the AIM XML documents.

It's here in the REST API documentation though. The solution.id field is immediately followed by the terminalNumber (which is not supported by this package at this time) and then the order.invoiceNumber. Your $this->addSolutionId($data); comes immediately before $this->addBillingData($data); and the first field added in that method is order.invoiceNumber, so I'm happy that the order is correct.

So I'm confident that the order is correct, but we do lack some tests that feed ALL possible fields into the request and check the result is in the correct order. It is just too easy to add a new field that works when you try it out, but may fail for someone using another field that you don't happen to use.

I'll merge in this PR anyway, as this field has no effect if not used, but we do need to extend the tests to include it.

[hillelcoren]

Thanks for merging the change!

[judgej]

A few more PRs then I'll do a release,