It seems the shortcut check should be with angles, not radius
It seems the shortcut check should be with angles, not radius

With many (100,000) circle symbols, the shortcut was not being taken
resulting in over 30% of the time in the update() for arc calculating
sin and cos. This fix lowers the time evaluating arc bounds to about 5%
and increases the frame rate.

I think this check is sufficient for the circle symbol, but there may be
able to be a stronger check for other full-circle arcs (other multiples of tau,
negative multiples of tau?).

vega/vega,lgrammel/vega,vega/vega,vega/vega,vega/vega