correctly parse n_jobs=-1 (#96)

[jpweytjens]

index_split can not parse n_jobs = -1. A solution is to pass the actual maximum number of cpu cores instead, as provided by joblib.cpu_count

[codecov]

Codecov Report

Merging #102 into master will decrease coverage by 0.02%.
The diff coverage is 50%.

@@            Coverage Diff             @@
##           master     #102      +/-   ##
==========================================
- Coverage    77.2%   77.17%   -0.03%     
==========================================
  Files          33       33              
  Lines        2338     2340       +2     
  Branches      376      377       +1     
==========================================
+ Hits         1805     1806       +1     
+ Misses        408      407       -1     
- Partials      125      127       +2

Impacted Files	Coverage Δ
recordlinkage/base.py	80.31% <50%> (-0.17%)	⬇️
recordlinkage/algorithms/compare.py	0% <0%> (ø)	⬆️

---

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[codecov]

Codecov Report

Merging #102 into master will decrease coverage by 0.02%.
The diff coverage is 50%.

@@            Coverage Diff             @@
##           master     #102      +/-   ##
==========================================
- Coverage    77.2%   77.17%   -0.03%     
==========================================
  Files          33       33              
  Lines        2338     2340       +2     
  Branches      376      377       +1     
==========================================
+ Hits         1805     1806       +1     
+ Misses        408      407       -1     
- Partials      125      127       +2

Impacted Files	Coverage Δ
recordlinkage/base.py	80.31% <50%> (-0.17%)	⬇️
recordlinkage/algorithms/compare.py	0% <0%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 87a5f4a...e493019. Read the comment docs.

[J535D165]

Thanks for your contribution @jpweytjens