- updated selected objects handling via the new selectionsAdded/ selectionsRemoved events from the polymer-threejs:  * attempting to implement group transforms (multi select) : not there yet ! - added various ui elements for export format selection - various minor adjustments , experiments etc
- updated selected objects handling via the new selectionsAdded/
selectionsRemoved events from the polymer-threejs:
 * attempting to implement group transforms (multi select) : not there yet !
- added various ui elements for export format selection
- various minor adjustments , experiments etc

usco/usco-proto