Implemented R's split() utility to split a sequence by a grouping factor.

[LTLA]

…tor.

[codecov]

Codecov Report

❌ Patch coverage is 96.07843% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.01%. Comparing base (e1acbfe) to head (a633982).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/biocutils/split.py	96.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #36      +/-   ##
==========================================
+ Coverage   90.87%   91.01%   +0.14%     
==========================================
  Files          42       43       +1     
  Lines        1786     1837      +51     
  Branches      359      375      +16     
==========================================
+ Hits         1623     1672      +49     
- Misses        112      113       +1     
- Partials       51       52       +1     

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[LTLA]

Best leave compressed_list out of this: (i) avoid cyclic dependency on compressed-lists, (ii) compressed-lists already has split_as_compressed_list(), and (iii) split() and splitAsList() are separate functions in R anyway.