use intensities cc1/2. support abismal colnames

[kmdalton]

Make careless.cchalf use intensities not structure factors. Make it support both "Sig{I,F}" and "SIG{I,F}".

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.19%. Comparing base (9a36aa6) to head (3ccabfb).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #191      +/-   ##
==========================================
+ Coverage   83.09%   83.19%   +0.09%     
==========================================
  Files          53       53              
  Lines        2532     2582      +50     
==========================================
+ Hits         2104     2148      +44     
- Misses        428      434       +6     

Flag	Coverage Δ
unittests	83.19% <100.00%> (+0.09%)	⬆️

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