anchor: love.physics.newCircleShape
  Creates a new CircleShape.
  shape = love.physics.newCircleShape( radius )
  radius number The radius of the circle.
  shape CircleShape The new shape.
  shape = love.physics.newCircleShape( x, y, radius )
  x number The x position of the circle.
  y number The y position of the circle.
  radius number The radius of the circle.
  shape CircleShape The new shape.