Recursion error in to_matrix

[Neclow]

Fix recursion error in to_matrix, like to_vector (see previous PR)

(Sorry for the short message, on the boat on a Saturday!)

I can add some rust code for that fix later

[deepsource-io]

Here's the code health analysis summary for commits cd49b7d..7254bef. View details on DeepSource ↗.

Analysis Summary

Analyzer	Status	Summary	Link
Rust	✅ Success	🎯 3 occurences resolved	View Check ↗
Python	✅ Success		View Check ↗

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[Neclow]

Added some rust code that somewhat repeats the python code I wrote, I'm not 100% sure how you usually operate with the different versions so I went ahead with both versions. Made a few design choices with the rust code, but happy to discuss/change

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Neclow]

Also fixed all current tests, which also pertain to #110. I suggest we can take some time Tuesday to explain the commits, or feel free to point out parts of the PR that should be better explained.

Another TODO would be to have more random tests like I wrote in the original package? e.g., for to_matrix, 1) sample a random matrix, 2) convert to newick, 3) convert back to matrix, 4) check that first matrix == second matrix