More structured documentation; simplify README

[tkf]

No description provided.

[codecov]

Codecov Report

Merging #54 into master will decrease coverage by 1.53%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #54      +/-   ##
==========================================
- Coverage   96.01%   94.48%   -1.54%     
==========================================
  Files           4        4              
  Lines         427      399      -28     
==========================================
- Hits          410      377      -33     
- Misses         17       22       +5     

Flag	Coverage Δ
#unittests	94.48% <ø> (-1.54%)	⬇️

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Impacted Files	Coverage Δ
src/macro.jl	93.10% <0.00%> (-3.16%)	⬇️
src/utils.jl	95.00% <0.00%> (-0.46%)	⬇️
src/reduce.jl	94.61% <0.00%> (-0.28%)	⬇️
src/checkboxes.jl	100.00% <0.00%> (ø)

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