Dynamic children

Fixes #1 


Actually, you can keep it here, but you should add some extra info about the added code (The fact that loadChild supports _n_ args and that the first one is the childName).

> Keys in this hash correspond with *refs* of child Components

This for example is no longer 100% true, keys represent the name and _most of the time_ the ref, because you can choose to return a specific ref in the .children method