Make Travis actually run tests
Make Travis actually run tests

The `script` key in `.travis.yml` needs an array if multiple test
scripts should be run. As it was, the harvest script was overriding the
nosetest script.
`leaflets` isn’t a valid harvest attribute, so no tests were running.
This now runs all features.

DemocracyClub/electionleaflets,DemocracyClub/electionleaflets,DemocracyClub/electionleaflets