func NewCodec() *Codec {
	return &Codec{}
}
----------------------------------------------------------------------------
Codec
----------------------------------------------------------------------------
NewCodec returns a new JSON Codec.
package json
import (
	"encoding/json"
	"net/http"
	"code.google.com/p/gorilla/rpc"
)
var null = json.RawMessage([]byte("null"))
type serverRequest struct {
	Method string `json:"method"`
	Params *json.RawMessage `json:"params"`
	Id *json.RawMessage `json:"id"`
}
type serverResponse struct {
	Result interface{} `json:"result"`
	Error interface{} `json:"error"`
	Id *json.RawMessage `json:"id"`
}