add PermMatrixCSC

[GiggleLiu]

We should gradually switch to the column majored permutation matrix for better performance.

NOTE: this is a non-breaking feature.

[codecov]

Codecov Report

Attention: Patch coverage is 88.61386% with 23 lines in your changes are missing coverage. Please review.

Project coverage is 91.38%. Comparing base (77ff1ed) to head (f9b46fc).
Report is 1 commits behind head on master.

❗ Current head f9b46fc differs from pull request most recent head 09f60d7. Consider uploading reports for the commit 09f60d7 to get more accurate results

Files	Patch %	Lines
src/conversions.jl	78.78%	7 Missing ⚠️
src/linalg.jl	84.09%	7 Missing ⚠️
src/PermMatrix.jl	93.47%	3 Missing ⚠️
src/arraymath.jl	85.71%	3 Missing ⚠️
src/promotions.jl	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #78      +/-   ##
==========================================
+ Coverage   88.85%   91.38%   +2.52%     
==========================================
  Files          14       14              
  Lines         754      789      +35     
==========================================
+ Hits          670      721      +51     
+ Misses         84       68      -16     

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[Roger-luo]

If it's non-breaking we should only bump patch version according to the convention. Don't bump the version inside PR.