[test.root] disable debug('uri')

*Producer#publish* supports `options.headers`

[Message] body default to null

[Message] fixed `body` in constructor

[Message] fixed `.fromRawMessage` headers

* [Message]

    - `.reject(options)` changed from `.reject(channel, options)`, `options` supports `multiple` and `requeue`. uses channel.nack instead of `channel.reject`
    - `.requeue()` uses `channel.nack` instead of `channel.reject`

Added Router,

[message] added .contentType, .contentEncoding