Create a VU meter widget

[joelholdsworth]

Create a VU meter widget that can be attached to the viewer. To be decided is whether this would be a large widget - 100s of pixels high to the height of the view screen to be shown next to it, or whether it would be a tiny meter that lives in the grip.

We also need a VU meter widget for the timeline track headers, could the same widget be universal for both?

[ichthyo]

reorganising core component tickets