have travis install dill to test pickling

Author: derek73

.travis.yml

@@ -9,6 +9,7 @@ python:
 # command to install dependencies
 install: 
   - if [[ $TRAVIS_PYTHON_VERSION == '2.6' ]]; then pip install --use-mirrors unittest2; fi
+  - "pip install dill"
   - "python setup.py install"
 # command to run tests
 script: python tests.py