Moved the position change to the less CPU intensive updateElement
Added (always visible) debug-buttons for:
- forcing a redraw
- outputting the paper.js structure to the console
Factored out the Elements class from NodeShape (will be reused in LinkShape)
Added source and target convenience getters to LinkShape
Remove dummy simulation elements
Improved indentation of source and improved appearance of buttons; fixed headers of Link overview
Improved send-to-front and send-to-back methods
Initial version of the event-based simulation behavior implementation.