* Add travis to run JS & CSS linting, JS tests, and PHPUnit tests
* Move API initiation out of the gutenberg/files check
So that php tests run without having to build the JS files
* Add very basic product endpoint tests
* Fix stylelint issues in CSS
* Remove e2e setup, replace with dependency setup
* Add missing install step
* Remove cache for now
* Add specific `har-validator` dependency because v 5.1.2 has disappeared
* Only run npm install for the JS test job
* Check for installed plugins
* Update install location
* Fix typo in plugin name
* Check the BRANCH variable, rather than TRAVIS_PULL_REQUEST_BRANCH, which is only set on PR runs
* Remove debug command
* A change to trigger CI
* Set the expected node & npm versions
* Remove copy-pasted command, does not apply