Implemented onActivate and onDeactivate callbacks

After the component rendered via Liberator, the parent component's refs don't point to child components anymore.

To get to child's DOM you should use the onActivate callback, providing you with the following information:

• layer - the layer to which liberated components are rendered to (multiple Liberators could render into the same layer)
• wrapper - wrapper element for component rendered by THIS Liberator
• children - original children provided to THIS Liberator

Stable version + 6 demos

1.0

Added Demo 6.