update compatible python versions for CI

Author: ncornette

Diff for: .travis.yml

@@ -2,9 +2,10 @@ language: python
 python:
   - "2.6"
   - "2.7"
-  - "3.2"
   - "3.3"
   - "3.4"
+  - "3.5"
+  - "3.6"
   # does not have headers provided, please ask https://launchpad.net/~pypy/+archive/ppa
   # maintainers to fix their pypy-dev package.
   - "pypy"