remove unnecessary require
refactor integration tests/setup

- shoestrap minitest reporter, just does not spit
  out huge strings when trying to match contents
  of a file. To be improved/replaced by custom
  matcher for file content later

- make it possible to specify which app to run the
  integration tests against. This allows us to
  verify arbitrary apps.

- split assertions up so we know exactly what
  fails

- extract test_app generation into setup task