Decorator support

[Jhen-Jie Hong]

I think it will be cleaner if we have decorator support:

@remotedev({ /* config */ })
export default class Counter {
  @observable counter = 0

  ...
}

@zalmoxisus, if you agreed I'll make a PR. :)

[Mihail Diordiev]

Definitely, it would be nice to have! :)

[Mihail Diordiev]

It's up in v0.2.3.