Adds internal method to Config

[mthadley]

I noticed internal was missing. Thanks!

[mthadley]

After thinking about this, I realized that this flag only makes sense for specific renderers. In this case , IncrementalDOMRenderer. Even then, it's only useful for Soy. Compare that to the other methods like required and value which make sense for all renderers. We could still add this, but now I'm thinking it might make more sense to add some kind of custom method instead?

So it could work like this:

MyComponent.STATE = {
  name: Config.string().value('test').custom('internal', true)
}

So custom would have a signature like custom(name : string, value : any).

[yuchi]

or…

MyComponent.STATE = {
  name: {
    internal: true,
    ...Config.string().value('test')
  }
}

[eduardolundgren]

@mthadley Would be good to expose on Config any valid configuration of State, the pull request looks good to me.

Everyone else is fine with the addition?

Thank you.

[mthadley]

Yea, that's ok. Just thought I would add an alternative solution. If you like it, I'm fine with merging it. @eduardolundgren