Add build step to travis

.travis.yml

@@ -8,6 +8,7 @@ install:
   - pip install -r requirements-dev.txt
   - pip install coveralls
 # command to run tests
+before_script: python setup.py build_ext --inplace
 script: nosetests --with-coverage --cover-package=schemamessages
 after_success:
   coveralls