Increment scale on running flows

[brandonreid]

For live running flows, we need to recalculate the scale as new data is added, at some increment. The goal being, when a flow completes, if you refresh the browser, you should see nodes at the same size as when watching the run live.

If the user manually adjust the scale, we'll need to accommodate that. Without looking deeply, we offer a reset button so that root value should still be available to key off of.