remove unsupported targets from tox.ini

tox.ini

@@ -1,8 +1,6 @@
 [tox]
 envlist =
-    py2.7-d1.5, py2.7-d1.6, py2.7-d1.7, py2.7-d1.8, py2.7-d1.9, py2.7-d1.10,
-    py3.3-d1.5, py3.3-d1.6, py3.3-d1.7,
-    py3.4-d1.7,
+    py2.7-d1.7, py2.7-d1.8, py2.7-d1.9, py2.7-d1.10,
     py3.5-d1.8, py3.5-d1.9, py3.5-d1.10
 
 [testenv]
@@ -11,15 +9,6 @@ commands = {envpython} tests/manage.py test django_messages --settings=settings
 
 # Python 2.7
 
-[testenv:py2.7-d1.5]
-basepython = python2.7
-deps = django>=1.5,<1.6
-       django-discover-runner
-
-[testenv:py2.7-d1.6]
-basepython = python2.7
-deps = django>=1.6,<1.7
-
 [testenv:py2.7-d1.7]
 basepython = python2.7
 deps = django>=1.7.1,<1.8
@@ -36,27 +25,6 @@ deps = django>=1.9,<1.9.99
 basepython = python2.7
 deps = django>=1.10,<1.10.99
 
-# Python 3.3
-
-[testenv:py3.3-d1.5]
-basepython = python3.3
-deps = django>=1.5,<1.6
-       django-discover-runner
-
-[testenv:py3.3-d1.6]
-basepython = python3.3
-deps = django>=1.6,<1.7
-
-[testenv:py3.3-d1.7]
-basepython = python3.3
-deps = django>=1.7.1,<1.8
-
-# Python 3.4
-
-[testenv:py3.4-d1.7]
-basepython = python3.4
-deps = django>=1.7.1,<1.8
-
 # Python 3.5
 
 [testenv:py3.5-d1.8]