Add Python 3.7 to CI.

.appveyor.yml

@@ -3,6 +3,7 @@ environment:
     TOXENV: py,codecov
 
   matrix:
+    - PYTHON: C:\Python37-x64
     - PYTHON: C:\Python36-x64
     - PYTHON: C:\Python27-x64
 

.travis.yml

@@ -1,13 +1,16 @@
 os: linux
+dist: xenial
 sudo: false
 language: python
 
 matrix:
   include:
+    - python: 3.7
+      env: TOXENV=py,simplejson,devel,lowest,codecov
+    - python: 3.7
+      env: TOXENV=docs-html
     - python: 3.6
       env: TOXENV=py,simplejson,devel,lowest,codecov
-    - python: 3.6
-      env: TOXENV=docs-html
     - python: 3.5
       env: TOXENV=py,codecov
     - python: 3.4

tox.ini

@@ -1,9 +1,9 @@
 [tox]
 envlist =
-    py{36,35,34,27,py}
-    py{36,27,py}-simplejson
-    py{36,27,py}-devel
-    py{36,27,py}-lowest
+    py{37,36,35,34,27,py}
+    py{37,36,27,py}-simplejson
+    py{37,36,27,py}-devel
+    py{37,36,27,py}-lowest
     docs-html
     coverage-report