def delta(to)
      diff = (to.to_f - self.to_f).abs % FULL_ANGLE
      diff = -(FULL_ANGLE - diff) if diff > Math::PI
      to.to_f < self.to_f ? -diff : diff
    end
def delta(to)
      diff = (to.to_f - self.to_f).abs % FULL_ANGLE
      diff = -(FULL_ANGLE - diff) if diff > Math::PI
      to.to_f < self.to_f ? -diff : diff
    end
Creates a new RTanque::Heading
 @param [#to_f] radians degree to wrap (in radians)
 difference between `self` and `to` respecting negative angles
 @param [#to_f] to
 @return [Float]