v0.4.0

• RBC, RBS, ZBS and ZBC are no longer written to configurations.csv,
  in both the DESC (desc_to_csv) and VMEC (vmec_to_csv) paths. These held the
  boundary surface Fourier coefficients as long comma-separated lists of numbers
  in scientific notation, which were unreadable in the database UI and were not
  used by anything.
• m and n in configurations.csv now hold the resolution of the boundary
  surface — the maximum poloidal and toroidal mode numbers of its double Fourier
  series — rather than the lists of mode numbers that accompanied the removed
  coefficient arrays. Each is now a single integer instead of a comma-separated
  list.
• The uploaded surface plot is no longer labelled with the configuration name
  (plot_surfaces is called without label), so it no longer carries a legend.
• Boundary elongation and curvature extrema in configurations.csv:
  max_elongation, min_elongation, max_curvature and min_curvature.
  Extrema are taken over absolute values. Elongation comes from
  a_major/a_minor and curvature from curvature_k2_rho, the second principal
  curvature of the boundary surface, in inverse meters.

Full Changelog: v0.3.0...v0.4.0