Tighten up configuration

[adamwight]

Interfaces\Config is unused. Tests and demo applications should be locally configured with a single file config.yaml.example, rather than in code.

I don't know what the config data should look like. It would be nice to include backend dependency injection, as well as defaults for each backend, but this seems like an overly complicated configuration file, it would look something like:

stomp:
    uri: tcp://host.localhost.net:61613
    read_timeout: 10

queues:
    test_stomp:
        backend: Stomp

[miccheng]

Hmm... Does PHP have a sane and build in YAML parser yet?

[adamwight]

I think package symfony/yaml is a good one, it's standalone and pure PHP.

On another note, sometimes we might want to provide configuration from calling code. Config::fromFile() and Config::fromArray() ?