Now with scatter-plot of information.

- No longer using glob.glob to read directories, since that also loaded
  the image files we were generating.
- Reading all images into memory at the beginning of the loop, so we
  don't have to do that several times.
- Scatter plot of exposure time and SDD, so we can see more information
  at a glance.
INI file changed to reflect "experiment" state
Plotting SDD vs. Exposure time, including labels

We now have a nice scatter plot of the SDD vs. the exposure time, this
makes differentiating between the lenses a bit easier.
Bringing these plots into the discussion on Wednesday.