Re-enable daemon mode for Kong, and update Serf and OpenResty
Re-enable daemon mode for Kong, and update Serf and OpenResty

Disabling daemon mode prevents tests from executing.

Furthermore, Kong can run fine with Serf 0.8.0,
and OpenResty 1.11.2.2.

The `Dockerfile` was updated to be as close as possible
to the Travis CI set up for `mashable/kong` on Github.

MrSaints/docker-kong-dev