This is going to be hard

It seems we are currently trying to run Chrome on Travis. Which is a
bit hard (https://github.com/travis-ci/travis-ci/issues/938). Firefox
is recommended:
https://docs.travis-ci.com/user/gui-and-headless-browsers/#Using-xvfb-to
-Run-Tests-That-Require-a-GUI

But it's still only Firefox.

We can keep the chrome work for local tests, but I think Travis should
ping Sauce Labs:
https://docs.travis-ci.com/user/gui-and-headless-browsers/#Using-Sauce-L
abs

So they can spin up 180 real browsers and test on those.

.travis.yml

@@ -15,7 +15,10 @@ cache:
   - node_modules
   - website/node_modules
 before_script:
+- export CHROME_BIN=chromium-browser
 - export PATH=${PATH}:${HOME}/bin
+- export DISPLAY=:99.0
+- "/sbin/start-stop-daemon --start --quiet --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -ac -screen 0 1280x1024x16"
 script:
 - npm run build
 - npm run test