piecharts.py: fix checkLabelOverlap for 3d pie
piecharts.py: fix checkLabelOverlap for 3d pie

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