ballcone cutter

[pppalain]

ballcone used to ask for
layout.prop(ao,'ball_radius')
layout.prop(ao,'Cutter_diameter')
layout.label(text='Cutter diameter = shank diameter')
layout.prop(ao,'ball_cone_flute')

the angle was calculated from those values.

we would like the UI to have a radio button to select either angle or cutter length and do the appropriate calculation for angle if it is not given