Separate action function and action name

[Calvin-Lin]

It's not convenient that every action function should have name property. https://github.com/Yoctol/bottender-recognizer/blob/master/src/index.js#L66

How about let resolver return action function and action name separately? Like this

const {name, action} = resolver(context.state, intent);

[chentsulin]

or may be we can implement something like this: https://github.com/acdlite/recompose/blob/master/docs/API.md#setdisplayname

[chentsulin]

https://github.com/Yoctol/bottender-compose/pull/57