adjust_shutter_and_gain_from_raw now uses a simpler algorithm.
The code is longer overall but hides some details in fuctions.
I've also split the loop into one for shutter speed and one for gain.
This isn't the algorithm that I originally wrote, but it seems to
work and is more readable.
numpy 1.20 deprecates np.float, which was only ever an alias for
``float``. I've replaced all occurrences of np.float with float, as
recommended. There should be no change in functionality.
The previous "auto calibrate" button for the camera relied on a
combination of the built-in autoexposure/AWB and
some JPEG-based tweaks to get the exposure settings right.
This often led to confusing results, e.g. oscillating between green and
pink images.
I have rewritten the auto-exposure code to adjust gain and shutter
speed based on the raw image. This seems to be
very reliable, at the expense of being quite slow. That's a price I'm
happy to pay.
I have replaced both the camera's auto white balance and my
JPEG-based AWB hack with a single-shot AWB method that
looks at the raw image.
