Simplify Postmark tracking webhook code by using new "RecordType"
field introduced with Postmark "modular webhooks". (Rather than
looking for fields that are probably only in certain events.)
Also issue configuration error on inbound url installed as tracking
webhook (and vice versa).
Existing tracking webhook code works fine with updated event payloads.
(So older Anymail versions will work, unmodified, with new Postmark
webhooks.)
Also update older doc links into Postmark docs.
Closes#101
Add support for Postmark's recently-released [delivery tracking webhook] to Anymail's normailized status event handling. The existing Anymail tracking webhook URL can be copied to "Delivery webhook" in your Postmark outbound server settings.
Closes#45.
* Restructure runtests.py as suggested in
https://docs.djangoproject.com/en/1.9/topics/testing/advanced/#using-the-django-test-runner-to-test-reusable-applications
* Load version-specific Django settings modules
(rather than trying to make a single settings.configure()
work with all supported versions).
* Use `django-admin startproject` defaults for all
settings modules. (Tests compatibility with typical
apps, middleware, and other settings.)
* Set up tests-specific url config; switch to literal
urls in test cases. (Eliminates url `reverse` from
tests.)
* Make runtests.py executable
Closes#18
