fix: use QR, add demo, add tests, add benchmark

[ghost]

Diff is due to a json file for benchmarking.

Ideas (for the future.)

• The arguments to helper functions toLatex, toString may actually need to be optional. This will require an API change.
• Unless data is standardised, calculations will blow up when higher degrees are used. The current demo shows this effect appears at n=7.

Comments

• Benchmark comparison to previous code shows it is approximately the same execution time.

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closes #10
closes #11

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (1008275) 97.76% compared to head (9ca51fb) 97.96%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #12      +/-   ##
==========================================
+ Coverage   97.76%   97.96%   +0.20%     
==========================================
  Files           1        1              
  Lines         179      197      +18     
  Branches       30       32       +2     
==========================================
+ Hits          175      193      +18     
  Misses          4        4              

Files	Coverage Δ
src/index.ts	97.96% <100.00%> (+0.20%)	⬆️

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