Merge pull request #69 from edx/benp/use-docker-travis

Use docker for builds.

.travis.yml

@@ -2,6 +2,9 @@ language: python
 python: "2.7"
 install:
     - "pip install coveralls"
+cache: pip
+# Use docker for builds
+sudo: false
 script:
     - make validate
     - git fetch origin master:refs/remotes/origin/master # https://github.com/edx/diff-cover#troubleshooting