shapes.py: make copy use derived class if not overridden
shapes.py: make copy use derived class if not overridden

makinacorpus/reportlab-ecomobile,makinacorpus/reportlab-ecomobile,makinacorpus/reportlab-ecomobile,makinacorpus/reportlab-ecomobile,makinacorpus/reportlab-ecomobile