Things that I have updated since running `make_sami_df` on the full data set

[hzovaro]

• Fixed bug where NaNs in the velocity maps were being overwritten by zeros (see issue #38)
  • Data affected: values in v_grad (component 1), Beam smearing flag (component 1); these will be incorrect
• Implemented a new flag to mark kinematic measurements where the measurement itself is NaN but the error is finite (see issue #36)
  • Data affected: no existing columns or cells (as confirmed by running regression tests) but new columns are added - Missing v_gas flag, etc.
• Implemented storage improvements (see issue #14, PR #54)
  • No data should be affected, but attempting to open the files with load_df will no longer work.

[hzovaro]

I have also manually renamed the following columns on the DataFrames in /data/misfit:

The following columns have been ADDED: x_0 (arcsec) y_0 (arcsec) HALPHA lambda_obs (Å) (component 1) HALPHA sigma_gas (Å) (component 1) [SII] ratio (total) [SII] ratio error (total) log [SII] ratio (total) log [SII] ratio error (lower) (total) log [SII] ratio error (upper) (total) The following columns have been REMOVED: Galaxy centre x0_px (projected, arcsec) Galaxy centre y0_px (projected, arcsec) HALPHA lambda_obs (component 1) (Å) HALPHA sigma_gas (component 1) (Å) S2 ratio (total) S2 ratio error (total) log S2 ratio (total) log S2 ratio error (lower) (total) log S2 ratio error (upper) (total)