- more work done on hover/selection:
 * currently hovered and currently selected objects are now amongst the attributes of the viewer
(can be very usefull for data binding etc)
 * a few changes to the selection helper for slightly easier use , but will need to be fully
refactored at some point (way too clunky as it is)
 * temporarly removed the more complex cage helper (displayed on selection) used in Coffeescad because of the more complex inheritance chain
and dependencies
 * various related cleanups and experiments