Merge pull request #14 from dhhagan/dev

fix travis

.travis.yml

@@ -1,17 +1,22 @@
 language: python
 python:
   - "2.7"
-  - "3.3"
-  - "3.4"
   - "3.5"
-  - "3.5-dev" # 3.5 development branch
-  - "nightly" # currently points to 3.6-dev
+
+before_script: # configure a headless display to test plot generation
+  - "export DISPLAY=:99.0"
+  - "sh -e /etc/init.d/xvfb start"
+  - sleep 3 # give xvfb some time to start
+
+before_install:
+  - sudo apt-get install -qq python-numpy python-scipy python-matplotlib
 
 install:
   - "pip install requests"
   - "pip install coverage"
   - "pip install coveralls"
   - "pip install pandas"
+  - "pip install seaborn"
 
 script:
   - "coverage run --source=openaq setup.py test"