Make confusion_matrix into a measure (orientation = :other). For 0.11.6 release

[ablaom]

#195 #168

[codecov-io]

Codecov Report

Merging #196 into master will decrease coverage by 2.08%.
The diff coverage is 66.66%.

@@            Coverage Diff            @@
##           master    #196      +/-   ##
=========================================
- Coverage   82.99%   80.9%   -2.09%     
=========================================
  Files          31      31              
  Lines        1970    1985      +15     
=========================================
- Hits         1635    1606      -29     
- Misses        335     379      +44

Impacted Files	Coverage Δ
src/measures/registry.jl	55.55% <ø> (ø)	⬆️
src/resampling.jl	87.32% <ø> (ø)	⬆️
src/measures/confusion_matrix.jl	48.88% <66.66%> (-48.45%)	⬇️

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