test against Django 1.7

tox.ini

@@ -51,7 +51,7 @@ deps =
 [testenv:py27]
 basepython = python2.7
 deps =
-    https://www.djangoproject.com/m/releases/1.7/Django-1.7c1.tar.gz#egg=Django
+    Django>=1.7.0
     mock
     jinja2
     futures
@@ -59,7 +59,7 @@ deps =
 [testenv:pypy]
 basepython = pypy
 deps =
-    https://www.djangoproject.com/m/releases/1.7/Django-1.7c1.tar.gz#egg=Django
+    Django>=1.7.0
     mock
     jinja2
     futures
@@ -68,13 +68,13 @@ deps =
 basepython = python3.3
 deps =
     jinja2
-    https://www.djangoproject.com/m/releases/1.7/Django-1.7c1.tar.gz#egg=Django
+    Django>=1.7.0
 
 [testenv:py34]
 basepython = python3.4
 deps =
     jinja2
-    https://www.djangoproject.com/m/releases/1.7/Django-1.7c1.tar.gz#egg=Django
+    Django>=1.7.0
 
 [testenv:docs]
 basepython = python2.7