cannonical embedding and changement of organization in the Display3D related classes

summary in the commit 2c52bd4 : 
has changed the class display3D into a template one
make specific children classes for factory, drawableWith, drawWithModifier, etc
add a cannonical embedding system into display3D which impacted the factories, tests, etc
update the documentation according to the changes


and moved  some misplaced parts from the add...( ... ) functions in Display3D into the factory