Configure travis-ci.org tests

Test Django 1.2 and 1.3; Python 2.6 and 2.7

Don't bother testing Python 2.5 -- it requires an older version of
requests (that doesn't depend on json).

Don't bother testing Django 1.2 -- it requires changes to ``assertRaises``
in the test cases (because the context-manager version of assertRaises is
part of unittest2, which appears in Django 1.3+ or Python 2.7+).

Don't bother testing Django 1.5 (yet).

.travis.yml

@@ -0,0 +1,11 @@
+language: python
+python:
+  - "2.6"
+  - "2.7"
+env:
+  - DJANGO_VERSION=1.3
+  - DJANGO_VERSION=1.4
+install:
+  - pip install -q Django==$DJANGO_VERSION
+  - pip install . --use-mirrors
+script: python setup.py test

README.rst

@@ -1,6 +1,9 @@
 Djrill, for Mandrill
 ====================
 
+.. image:: https://travis-ci.org/brack3t/Djrill.png
+        :target: https://secure.travis-ci.org/brack3t/Djrill
+
 Djrill is an email backend and new message class for Django users that want to take advantage of the Mandrill_ transactional
 email service from MailChimp_.
 
@@ -110,6 +113,13 @@ extra headers are silently discarded.
 Testing
 -------
 
+Djrill is tested against Django 1.3 and 1.4 on Python 2.6 and 2.7.
+(It may also work with Django 1.2 and Python 2.5, if you use an older
+version of requests compatible with that code.)
+
+.. image:: https://travis-ci.org/brack3t/Djrill.png
+        :target: https://secure.travis-ci.org/brack3t/Djrill
+
 The included tests verify that Djrill constructs the expected Mandrill API
 calls, without actually calling Mandrill or sending any email. So the tests
 don't require a Mandrill API key, but they *do* require mock_