Node ordering

[davide-f]

This commit attempts to solve the issue #12 to set the ordering of selected nodes.

This branch is also the updated version of previous #17 ; it is built on top of the pull request #16 where the tests are modified to accommodate optional arguments.

[codecov-commenter]

Codecov Report

Merging #19 (aeadf16) into main (baea9a4) will increase coverage by 0.13%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #19      +/-   ##
==========================================
+ Coverage   92.09%   92.22%   +0.13%     
==========================================
  Files           4        4              
  Lines         177      180       +3     
==========================================
+ Hits          163      166       +3     
  Misses         14       14              

Impacted Files	Coverage Δ
src/zarate.jl	90.51% <100.00%> (+0.25%)	⬆️

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[davide-f]

@oxinabox Thank you for your interest on the other PR #16 ; may you crosscheck also this PR (it was inherited from the old #17 )
CI works and I added also other tests. Once the PR #16 is merged, we may merge also this one

[oxinabox]

this will now need rebasing as i merged your other PR

[davide-f]

@oxinabox Done; I also set the input type to be Vector{Pair}

[oxinabox]

Nice LGTM