test running of rep image for everware in CI

[anaderi]

e.g. add test that after building image in circle.yml, the script starts the image with variables mocking jupyterhub environment (JPY_API_TOKEN, JPY_GITHUBURL, JPY_COOKIE_NAME, JPY_BASE_URL, JPY_HUB_PREFIX, JPY_HUB_API_URL) and checks that it started properly by connecting to localhost://8888.

[arogozhnikov]

you can use current tests at CircleCI as starting point (same tested for jupyter).