Add path length option to sholl analysis

[arnaudon]

By default the Sholl analysis is done wrt radial euclidean distance, but having path distance as an optional metric for Sholl analysis is sometimes useful.
This PR provides such functionality via an additional parameters distance_type.

[eleftherioszisis]

LGTM. Maybe @andrisecker has some comments?

[arnaudon]

He is trying it, once he's happy with the result, we can merge!

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (0ca89b0) to head (262b851).
Report is 42 commits behind head on master.

❗ Current head 262b851 differs from pull request most recent head b73a08a. Consider uploading reports for the commit b73a08a to get more accurate results

Additional details and impacted files

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  Coverage   100.00%   100.00%           
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[arnaudon]

@andrisecker , are you good with this? Is it doing what you wanted?

[arnaudon]

@andrisecker are you still using this? do you think its worth merging or not?

[andrisecker]

@arnaudon I'm not using it any more, but I think if I had this use case and it's already implemented then you should merge it.

[arnaudon]

@eleftherioszisis I let you double check and approve this when you have time, as I cannot merge

[arnaudon]

rebase is a pain, and this feature is not used, I discard..