Added travis and tox configuration for pypy 2.7 and 3.5.

.travis.yml

@@ -17,6 +17,10 @@ matrix:
       env: TOXENV=py35
     - python: 3.6
       env: TOXENV=py36
+    - python: pypy2.7
+      env: TOXENV=pypy27
+    - python: pypy3.5
+      env: TOXENV=pypy35
 
 install:
   - pip install tox

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 1.7.2
-envlist = flake8, py3flake8, py27, py33, py34, py35, py36
+envlist = flake8, py3flake8, py27, py33, py34, py35, py36, pypy27, pypy35
 skip_missing_interpreters = true
 
 [testenv]