bug 1382622, add environment to test python 2.7 with compare-locales, r=stas

compare-locales doesn't support py3 yet, so we don't add that
environment yet.

This adds tox-travis, so that we can add dependency management in
tox, and use travis to run individual jobs per python version.
Compare-locales or not are run in the same travis job.

Author: Pike

.travis.yml

@@ -1,9 +1,11 @@
+sudo: false
 language: python
 python:
   - "2.7"
   - "3.5"
   - "nightly"
-script: python -m unittest discover
+install: pip install tox-travis
+script: tox
 notifications:
   irc:
     channels:

tox.ini

@@ -1,8 +1,11 @@
 [tox]
-envlist = py27, py36
+envlist = py27, py27-cl, py36
 skipsdist=True
 
 [testenv]
 setenv =
     PYTHONPATH = {toxinidir}
+deps =
+    cl: compare-locales
+
 commands=python -m unittest discover