Wrap api methods with a custom one to remove need for rewriting protocol

[usirin]

This removes the need for munging callbacks etc.

Instead of us rewriting the protocol, we are simply wrapping each function with a one that can understand the way we are sending messages, and transforms this dnode-request into our function calls by simply sending arguments in the correct order.

This also adds the request info as the last argument to the method handlers.

[usirin]

@gokmen let's merge this i will send other changes in another pr.