Huge Refactor

• Client and server are now in the porthos (top level) package.
• Server now has a blocking ListenAndServe function.
• Server now has Close (async shutdown) and Shutdown (blocking shutdown).
• Server now has RegisterWithSpec function to provide a spec alongside with the handler function.
• Added a built-in extension to ship (to the playground app) all registered procedures with specs.
• Status code constants were renamed after moved to the top level package (porthos).

New arguments API

Now the Client exposes a little DSL to make RPC calls:

// async call
responseChan, err := serviceClient.Call("addOne").WithArgs(10).Async()

// sync call
response, err := serviceClient.Call("addOne").WithArgs(10).WithTimeout(2 * time.Second).Sync()

// call void
serviceClient.Call("doSomething").WithBody(bytes).Void()

The method name now is being transported in a custom Header (X-Method) and the request body goes into AMQP message body directly.

First official release

Since @eventials started using porthos-go, we feel good enough to announce the first release. \o/