Manual QR code cycling

## Issue:
The QR code cycling is entirely broken on my machine, phone, and Jade. None of the devices are able to register any of the other devices QR codes.

## Example:
The phone via the Green app, for example, reads a few of the QR codes then fails to read one. Instead of any resuming feature, the phone restarts scanning from the first QR code. This process repeats forever and the series of QR codes is never read.

## Desired Behavior:
* Add the ability to manually click through one QR code at a time. This allows 1) A user to manually decode the QR codes, and, 2) allows for slower QR code scanners to keep up.
* Make the QR code scanner be able to resume "in-place." This means if a scan fails, it does not start from the beginning but instead waits for the cycle to come back around

Start by tracing the C implementation that cycles QR codes and the scanner interaction; the issue does not name specific files or tests. Verify the behavior on the phone and Jade examples described, then make completion mean that users can advance one QR code at a time and that failed scans resume at the current position rather than restarting.

Written by the indexing model from the issue text.