Properly handle list URLs with query params

Upcoming invoices use a URL of the form
`/v1/invoices/upcoming/lines?customer=cus_4ozMxJvDf1vy39` for their
`url` field. This breaks calls to `Stripe_List` on
`$upcoming_invoice->lines`.
Merge pull request #108 from stripe/lists_with_query_params

Properly handle list URLs with query params
Update CHANGELOG

We never released 1.17.2, so let's add the small change into it and release. Will be more rigorous about version releasing in the future.