Attempt to use the latest Python versions to workaround datetime issues.

jamesblackburn · jamesblackburn · commit 6df008bf5f63 · 2016-07-01T11:22:19.000-04:00
https://bugs.python.org/issue23600 dateutil/dateutil#158
diff --git a/.travis.yml b/.travis.yml
@@ -2,8 +2,8 @@ sudo: false
 language: python
 python:
   - "2.7"
-  - "3.4"
-  - "3.5"
+  - "3.4.4"
+  - "3.5.1"
 install:
   - pip install --upgrade pip
   - pip install python-dateutil --upgrade
