Add "Could not build calibration graph" error description #68
Description
It would be good to add a section on this error:
ValueError:
Could not build calibration graph.
Some group of cameras could not be paired by simultaneous calibration board detections.
Check which cameras have different group numbers below to see the missing edges.
{0: 0, 1: 3, 2: 2, 3: 3, 4: 4}
in the documentation. Specifically, it should be in this section.
It would be good to explain the output (camera:group) and a short bit about the error