Added SoapResponseListener

This listener allow return a raw result from the action.

Before:
    /**
     * @Soap\Method("hello")
     * @Soap\Param("name", phpType = "string")
     * @Soap\Result(phpType = "string")
     */
    public function helloAction($name)
    {
        return $this->container->get('besimple.soap.response')->setReturnValue(sprintf('Hello %s!', $name));
    }

After:
    /**
     * @Soap\Method("hello")
     * @Soap\Param("name", phpType = "string")
     * @Soap\Result(phpType = "string")
     */
    public function helloAction($name)
    {
        return sprintf('Hello %s!', $name);
    }