add the ability for a custom reality to show live video

[blairmacintyre]

We've talked about giving the app the ability to tell users "Go stand on this spot to get a good AR view" and then fixing the location to the known location at that spot. To do this, we could create a custom reality with a command to set the location.

[blairmacintyre]

Better idea (thanks to Gheric for the idea): have the reality be a superset of the panorama reality, which can switch between pano's a live video depending on where the user is.

Essentially, we could modify the pano reality to be able to show "live video as a pano" at a certain spot.