After cloning the repo and running: `docker build -t localstack:latest .`
I can see the following errors:

```
Starting mock Lambda service (http port 4574)...
ERROR: Error forwarding request: HTTPConnectionPool(host='127.0.0.1', port=4564): Max retries exceeded with url: / (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f4c7b4e7c10>: Failed to establish a new connection: [Errno 111] Connection refused',)) Traceback (most recent call last):
  File "/opt/code/localstack/localstack/services/generic_proxy.py", line 216, in forward
    headers=forward_headers, stream=True)
  File "/opt/code/localstack/.venv/lib/python2.7/site-packages/requests/api.py", line 116, in post
    return request('post', url, data=data, json=json, **kwargs)
  File "/opt/code/localstack/.venv/lib/python2.7/site-packages/requests/api.py", line 60, in request
    return session.request(method=method, url=url, **kwargs)
  File "/opt/code/localstack/.venv/lib/python2.7/site-packages/requests/sessions.py", line 524, in request
    resp = self.send(prep, **send_kwargs)
  File "/opt/code/localstack/.venv/lib/python2.7/site-packages/requests/sessions.py", line 637, in send
    r = adapter.send(request, **kwargs)
  File "/opt/code/localstack/.venv/lib/python2.7/site-packages/requests/adapters.py", line 516, in send
    raise ConnectionError(e, request=request)
ConnectionError: HTTPConnectionPool(host='127.0.0.1', port=4564): Max retries exceeded with url: / (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f4c7b4e7c10>: Failed to establish a new connection: [Errno 111] Connection refused',))
```

I see the same thing when running `localstack start --docker` which is what I originally tried as I would like to use localstack for development purposes in an existing stack.

MacOS Mojave 10.14
Docker for Mac: 18.06.1-ce-mac73 (26764)
plugin_configs = load_plugins()
    plugin_run_params = ' '.join([
        entry.get('docker', {}).get('run_flags', '') for entry in plugin_configs])
    services = os.environ.get('SERVICES', '')
    entrypoint = os.environ.get('ENTRYPOINT', '')
    cmd = os.environ.get('CMD', '')
    image_name = os.environ.get('IMAGE_NAME', constants.DOCKER_IMAGE_NAME)
    service_ports = config.SERVICE_PORTS
    force_noninteractive = os.environ.get('FORCE_NONINTERACTIVE', '')
    
    ports_list = sorted(service_ports.values())
    start_port = 0
    last_port = 0
    port_ranges = []
    for i in range(0, len(ports_list)):
        if not start_port:
            start_port = ports_list[i]
        if not last_port:
            last_port = ports_list[i]
        if ports_list[i] > last_port + 1:
            port_ranges.append([start_port, last_port])
            start_port = ports_list[i]
        elif i >= len(ports_list) - 1:
            port_ranges.append([start_port, ports_list[i]])
        last_port = ports_list[i]
    port_mappings = ' '.join(
        '-p {start}-{end}:{start}-{end}'.format(start=entry[0], end=entry[1])
        if entry[0] < entry[1] else '-p {port}:{port}'.format(port=entry[0])