Remove unnecessary/unused canvas element.
Clean up whitespace/line length in videoShooter.
Letterbox images when they don't match aspect ratio.

We probably also need to handle orientation changes and flip the
width/height in those cases. I *believe* mobile browsers handle that
consistently. This should work better for the initial orientation,
although the black bars can be rather large. Ideally I think we could
try to get the browser to get us a resolution closer in aspect ratio
to what we want, although I haven't had much success with constraints
as of yet.

We could also consider doing some sort of cropping and/or zooming, we
just need to make sure the preview matches up with what we're doing
behind the scenes.
Use cropping instead of letterboxing.

This seems to be a more pleasing result, and the CSS has been
updated to apply the same crop. The resulting FOV looks very similar
to what the Android app used to generate.
Add handling for orientation changes.