Fixed Link force jiggling

src/link.js

@@ -45,7 +45,7 @@ export default function(links) {
         x = target.x + target.vx - source.x - source.vx || jiggle();
         y = target.y + target.vy - source.y - source.vy || jiggle();
         l = Math.sqrt(x * x + y * y);
-        l = (l - distances[i]) / l * alpha/* * strengths[i]*/;
+        l = (l - distances[i]) / l * alpha * strengths[i];
         x *= l, y *= l;
         target.vx -= x * (b = bias[i]);
         target.vy -= y * b;