- merge all APIPromise class
- remove IServerAPI and IClientAPI
- remove res Object, return [status, body] in ServerAPI instead
- remove schema classes, use interface instead
- `-s` flag for `ctx.state` interface path
ClientAPI: use Axios
ServerAPI: use @koa/router
FullDate: wrapped Date only class
APIPromise: enhanced Promise on api response
application/json only(multipart/*, image/*, ... are not supported)
get, post, put, delete, patch only
