fix #349 maximizable Dialog service pack

[jakub-g]

Fixed issues with:

1. Dialog maximized from start
2. Resizing Dialog while maximized
3. Resizing viewport while Dialog maximized
4. Unmaximizing the Dialog after full section refresh

Additionally:

1. Perf and readability improvements (changeProperty vs
   setProperty).
2. Test for destroying/creating Draggable/Resizable.

[jakub-g]

Ready for code review.

Basically what I've done is that now in maximized mode, the internal this._cfg.width|heightMaximized are used instead of this._cfg.width|height -- the original ones are untouched when maximizing, so they can survive a refresh.

Apart from that, there are small changes in the way Draggable and Resizable are handled (nullifying / creating empty container when needed) and changed the way how maximization works by implicitly calling the necessary functions instead of waiting for _onBoundPropertyChange to fire after changeProperty is called.

I've added a lot of unit tests and also tested manually on the demo site.

[piuccio]

Integrated in 5e7cb61