Change events trigger immediate render calls

[Beanow]

Currently the base-store provides a change event which triggers immediately when the internal data has been updated. However, for actions that span multiple entities, each store will trigger this event before all stores are updated.

This causes for ugly rendering methods that check for stores that are not done processing the action yet. The principles document for Actions states that:

...stores should never be in an inconsistent state after the dispatcher has dispatched an Action.

Note that this says, after the dispatcher has dispatched an Action, not during.
I think stores should wait until dispatching has completed before triggering the change event.