Support i18n, such as logs and internal messages

[iohao]

Support internationalization, such as logs, messages. This tool will be used internally only.

计划新增支持国际化的工具类，该工具仅用于框架内的日志、内部消息等。

[iohao]

public class DemoApplication {
    public static void main(String[] args) {
        // setting defaultLocale, such as US or CHINA
        Locale.setDefault(Locale.US);
        Locale.setDefault(Locale.CHINA);

        ... start ioGame
    }
}