Fix upstart scripts to only start when dependent services are up

Should ensure that after running `vagrant reload`, the `celeryd`, `tiler`, and `ecoservice` jobs will be running.

Fixes #21 
This would be clearer if we renamed `celeryd` to `otm-celery`. This process is not any more generic than the `otm-unicorn` process (which I always thought should be called `otm-gunicorn`).