Small css fix that allows us to have 2 large buttons next to each other

Thanks @trasher
Small clean up in the css
Change by_election_and_name to by_election_file_and_name

The filename and the candidate_name together should be unique
to a given election thus having two methods is incorrect.
Fix the internal API for the changes made to the model about by_election_file_and_name
Fix the unit-tests to work with the new API and check the correct behavior in the UI