Add camera underlay.

[Aphexus]

It would be very useful to add a camera underlay. This should be easy to do but what it does is let one look at the screen and not just see the map but also the sky. That should be pretty easy to do.

From there it might be possible to also lock the map on to the sky by using a correlation test since bright stars should be be mapped(e.g., scan the input image for stars and then try to map them to the map. If enough stars are visible it should be relatively easy to get an accurate map).