Flyby camera workflow improvements

[GeckoKid-JW]

As discussed at Derby, could we have an option to

1. Change the preview cone of the flyby from a circle to a rectangle to more accurately preview what the camera is seeing
2. Ability to change the size of the flyby camera box/icon, which will be extremely useful in a very dense cutscene
3. Even if we can't preview the flyby (which would be awesome) Could we have a button/hotkey to snap to view from the selected camera to preview what we are looking at?

[GeckoKid-JW]

On 3. As well perhaps when previewing it could automatically toggle visibility of all the flyby cameras until you move the viewport again.

[WalrusTR]

I'd suggest also 4 buttons to move to the previous/next camera and to jump to start/end of flyby sequence without exit from flyby window.