Remove tox support for Django 1.4-1.7, add support for 1.11tip and 2.0tip

Author: Pamela McA'Nulty

tox.ini

@@ -14,23 +14,20 @@
 
 [tox]
 envlist =
-    py27-django{14,15,16,17,18,19,110,110tip,tip},
-    py34-django{15,16,17,18,19,110,110tip,tip},
-    py35-django{18,19,110,110tip,tip},
-    py36-django{18,19,110,110tip,tip},
+    py27-django{18,19,110,110tip,111tip},
+    py34-django{18,19,110,110tip,111tip,tip},
+    py35-django{18,19,110,110tip,111tip,tip},
+    py36-django{18,19,110,110tip,111tip,tip},
     check,doc
 
 [testenv]
 deps =
     unittest-mixins==1.1
-    django14: Django >=1.4, <1.5
-    django15: Django >=1.5, <1.6
-    django16: Django >=1.6, <1.7
-    django17: Django >=1.7, <1.8
     django18: Django >=1.8, <1.9
     django19: Django >=1.9, <1.10
     django110: Django >=1.10, <1.11
     django110tip: https://github.com/django/django/archive/stable/1.10.x.tar.gz
+    django111tip: https://github.com/django/django/archive/stable/1.11.x.tar.gz
     djangotip: https://github.com/django/django/archive/master.tar.gz
 
 commands =