Fixed bug in QuadraticBezier.length()
Fixed bug in QuadraticBezier.length()

Now method supports all possible quadratics.
Previous, the method did not support curves with
inner_product(a,b) == -|a||b|, 
where a = P0 - 2P1 + P2 and b = 2(P1 - P0) .
regebro/svg.path