dhotson/springy — pull request #33 by dhotson (2013-03-14 12:19:52+00:00)
Title: Option to manually tick simulation forward

This adds the ability to manually tick the layout simulation.

eg
```js
var layout = new Layout.ForceDirected(graph, stiffness, repulsion, damping);

for (var i=0; i<1000; i++) {
layout.tick(0.01);
}
```