- fixed issue with layout staying in a `busy` state when it quits before laying out
- added method `widgie.layout.Layout#forceLayout`
- `widgie.layout.Layout#afterLayout` is now a delayed callback
- changed base observers for layout to listen to new event `change:dom`
- `widgie.data.Store#load` now only adds data and broadcasts `change:data` event if there are items to add, otherwise it will broadcast the `load:empty` event