Fix connected trees
Remove all "data-" from ui-tree attributes
Update bower components for demo
Fix callbacks sent from node
Make ui-tree ract to event for collapse/expand all
Now that scopes are isolated, it's no more possible to call a ui-tree
method from outside.
So we have to use events.

If you want more events to be supported, just open an issue.
Emit callbacks from the right scope. In this case: tree
Update demo for collapse/expand all events support
Update demo ui-tree release