Safeframe for video editor

Once the option is selected, it turns rendering into a 2 click process: the first click on the "render" will enable the safe-frame and you can still navigate/change settings, then another click on the same button will render it.

But it has been mentioned before and I agree fully: it should just toggle the view rather than work this way.

Gadget, jtubb - I will create a feature request for consideration of the Safe Frame to be toggled.