No namespace and a strange "type" for Requester and Responder instances

Hello @dashersw

Following development of the c-cote library, I notice that the Requester and Responder do not use namespace and topic at all, instead a "type" field is required to have a kind of topic.

Is it something that is really wanted ? or working on the API still needed ? What append if "type" is an applicative information the user want to send ?

Actually the API of the publisher looks like:

```
randomPublisher.publish('topic', json);
```

I imagine Requester can be :

```
randomRequest.send('topic', json, function(res) {
//handle res
});
```

With usage of the topic and namespace of course.

I have created a small doc on messages format at https://github.com/joelguittet/c-cote/wiki/Format-of-Cote-messages. In my dreams the format of messages between Requester and Responder looks like between Publisher and Subscriber:

```
+-----------+-------------+-------------+-------+-------------+----------------+
| Fulltopic | AMP field 1 | AMP field 2 | ..... | AMP field N | `pid:id` field |
+-----------+-------------+-------------+-------+-------------+----------------+
```

With fulltopic : `message::::`

Note I suggest on this schema to permit sending any type of AMP fields (blob - useful for sending audio, json, string and bigint), and several fields of course, because it's permitted by axon. The "pid:id" is added by axon itself.

This can be the beginning of a discussion on the subject if you want. Your namespace idea is really not bad and will be a nice to have on Req/Rep in my opinion.

Joel

EDIT: just seen this issue too: https://github.com/dashersw/cote/issues/165. Not sure about this concept of "subset" instead of namespace.