language: python
python:
  - '3.6'
install:
  - pip install .
before_script:
  - "ls -R"
  - "export DISPLAY=:99.0"
  - "sh -e /etc/init.d/xvfb start"
  - sleep 3 # give xvfb some time to start
script:
  - py.test

language: python
python:
  - '3.6'
install:
  - pip install .
before_script:
  - "ls -R"
script:
  - xvfb-run py.test

Update how xvfb is started in Travis.
Update how xvfb is started in Travis.

At some point Travis introduced a new way to start xvfb, and apparently
broke the old way (possibly depending on which distribution you ask
for).  In any case, I needed to update my tests.  See below for more
details:

https://docs.travis-ci.com/user/gui-and-headless-browsers/#using-xvfb-to-run-tests-that-require-a-gui
