Initialize Viewer with fit to specified bounding box

[garrettdashnelson]

Feature-request (and if this is already an implemented feature, I apologize for not being able to find it, either in Clover or OSD!).

I would like to be able to initialize a Viewer component with parameters that set it to fit the view to a specified bounding box within the initial image.

I know that I can pass defaultZoomLevel to options.openSeadragon to force a zoom-in around the centerpoint. But what I'd like to do is a bit more specific, fitting the view to a specified bounding box within the image, equivalent to what one could do in OpenLayers with View.fit().