Dropping support for Django 1.5 and 1.6; adding support for Django 1.8.

.travis.yml

@@ -5,10 +5,9 @@ python:
 - '3.3'
 env:
   matrix:
-  - DJANGO=1.4.14
-  - DJANGO=1.5.9
-  - DJANGO=1.6.8
-  - DJANGO=1.7.1
+  - DJANGO=1.4.20
+  - DJANGO=1.7.8
+  - DJANGO=1.8.2
   global:
   - secure: aswHU7pQroGM+GHoYlhXzzk2FYfqxXJORjqXPsbgoHAIu4Bssaj8+YAzIcdy3j9kSt4I8VBpjnn8H/wzQXki75JBZOosQrIeMK018+uR+ZMONBLqDYW/N7EJHLgZt9QXxQNKeZygrD4GN/Dc4gLHGvPQC/RfPuuHcnF0Liaahoo=
   - secure: RZ6M6984P885GRoyx9n/WCCWGoFAzYpS8sZkXu3e/HK9oPXfaM2IEHjkq03jIC/FcWn/QMtFjOUBqQU94rnqdivFdFkeZHk1WUQgC0hztH3Qhh9zu2PNIrYUDpVD5dJqBpprWbSwFP8yNsJlP9A2RUubTlZblKHuaBhhiuNN+kU=

django_mailbox/runtests.py

@@ -23,7 +23,10 @@ if not settings.configured:
         ]
     )
 
-from django.test.simple import DjangoTestSuiteRunner
+try:
+    from django.test.runner import DiscoverRunner as TestRunner
+except ImportError:
+    from django.test.simple import DjangoTestSuiteRunner as TestRunner
 
 
 def runtests(*test_args):
@@ -37,7 +40,7 @@ def runtests(*test_args):
     except NameError:
         # This version of Django is too old for an app registry.
         pass
-    runner = DjangoTestSuiteRunner(
+    runner = TestRunner(
         verbosity=1,
         interactive=False,
         failfast=False