Add coveralls

.travis.yml

@@ -18,7 +18,10 @@ install:
   - pip install lxml
   - pip install pyquery
   - pip install cairosvg
+  - pip install coveralls
 
 script: py.test pygal/test --flake8 --cov-report= --cov=pygal
 
+after_success: coveralls
+
 sudo: false