Taking pictures at lower resolutions can be several times faster than at 1920×1080, so we should provide calibrated focal lengths for as many resolutions as possible.

This is caused by time_left being None when the reaper is disabled.

in debug mode, should default to continious execution. Current verbage is confusing, the checkbox should be "Timed Run" and default to off(not timed).

Shepherd should be able to pass an --image-file command-line argument that allows sr.robot to save its images to the filesystem – this will allow us to e.g. show images in the web UI, or to save them to a USB stick.

So that we can potentially do both of these at once, sr.robot should be able to accept multiple places to save the image to.

On import of sr.robot, each ThunderBorg object that's created spews out several lines of logs – this should only be the case for boards we actually managed to communicate with.

Attempting to access a ThunderBorg that isn't attached should raise an exception.