Add jenkins.sh to test and build

Also rearrange build_artefact.sh and run_tests.sh to be a bit more
consistent and expect a virtualenv to already be activated.
Remove post test tagging from travis config

This will now be done on the CI box
Merge pull request #30 from alphagov/add-jenkins

Add jenkins.sh to test and build
Merge branch 'master' into fix-treemap-department-grouping