Make optimal number of components of all criteria accessible

[eurunuela]

Closes none.

This PR makes the optimal number of components calculated with AIC, KIC, and MDL accessible with the class regardless of the user-selected criterion.

[eurunuela]

The first commit is actually from #47.

[codecov-commenter]

Codecov Report

Merging #48 (3a8e1d1) into main (0ae41bb) will decrease coverage by 0.42%.
The diff coverage is 83.33%.

@@            Coverage Diff             @@
##             main      #48      +/-   ##
==========================================
- Coverage   90.42%   90.00%   -0.43%     
==========================================
  Files           3        3              
  Lines         282      290       +8     
==========================================
+ Hits          255      261       +6     
- Misses         27       29       +2     

Impacted Files	Coverage Δ
mapca/mapca.py	86.28% <81.25%> (-0.55%)	⬇️
mapca/__init__.py	100.00% <100.00%> (ø)

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[tsalo]

Happy to merge this as-is, but what about adding trailing underscores in the attribute names, per our sklearn-based convention?

[eurunuela]

Happy to merge this as-is, but what about adding trailing underscores in the attribute names, per our sklearn-based convention?

Agh, I keep forgetting that. Will do tomorrow, thank you Taylor!

[eurunuela]

Added trailing underscores. Merging assuming you're happy with the changes now.