ENH: Warn on invalid MINC2 spacing declarations, treat as missing

[petsuter]

Accept other values (like xspacing), assuming regular spacing. #1236

[codecov]

Codecov Report

Patch coverage: 80.00% and no project coverage change.

Comparison is base (064e80d) 92.16% compared to head (ba88e43) 92.16%.

❗ Current head ba88e43 differs from pull request most recent head 1402f18. Consider uploading reports for the commit 1402f18 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1237   +/-   ##
=======================================
  Coverage   92.16%   92.16%           
=======================================
  Files          98       98           
  Lines       12364    12368    +4     
  Branches     2539     2540    +1     
=======================================
+ Hits        11395    11399    +4     
  Misses        646      646           
  Partials      323      323           

Impacted Files	Coverage Δ
nibabel/minc2.py	90.47% <80.00%> (+0.47%)	⬆️

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[effigies]

We should test this. Opened a PR against your branch: petsuter#1

[effigies]

Thanks very much! Would you like to add yourself to the Zenodo file as a contributor?

https://github.com/nipy/nibabel/blob/master/.zenodo.json

[petsuter]

Thanks, done.