Test against Python 3.6, update coverage dependency which was broken with 3.6

.travis.yml

@@ -25,6 +25,8 @@ matrix:
       env: TOXENV=py35-1.10.X
     - python: 3.5
       env: TOXENV=py35-1.11.X
+    - python: 3.6
+      env: TOXENV=py36-1.11.X
 notifications:
   irc: "irc.freenode.org#django-compressor"
 after_success:

requirements/tests.txt

@@ -1,5 +1,5 @@
 flake8==2.4.0
-coverage==3.7.1
+coverage==4.4
 html5lib==0.9999999
 mock==1.0.1
 Jinja2==2.7.3

tox.ini

@@ -1,7 +1,7 @@
 [deps]
 two =
     flake8==2.4.0
-    coverage==3.7.1
+    coverage==4.4
     html5lib==0.9999999
     mock==1.0.1
     Jinja2==2.7.3
@@ -13,7 +13,7 @@ two =
     rjsmin==1.0.12
 three =
     flake8==2.4.0
-    coverage==3.7.1
+    coverage==4.4
     html5lib==0.9999999
     mock==1.0.1
     Jinja2==2.7.3
@@ -27,12 +27,14 @@ three =
 envlist =
     {py27,py33,py34,py35}-{1.8.X}
     {py27,py34,py35}-{1.9.X,1.10.X,1.11.X}
+    {py36}-{1.11.X}
 [testenv]
 basepython =
     py27: python2.7
     py33: python3.3
     py34: python3.4
     py35: python3.5
+    py36: python3.6
 usedevelop = true
 setenv =
     CPPFLAGS=-O0
@@ -49,4 +51,5 @@ deps =
     py33: {[deps]three}
     py34: {[deps]three}
     py35: {[deps]three}
+    py36: {[deps]three}
     django-discover-runner