Refactor optimize merge (#121)

* refactor: optimized merge detection

* bug: removed subroutine

* removed test tqdm

* bug: close zip writer

* refactor: metrics in pandas df

* refactor: detect all sites

* bug: empty merge list

* bug: rescaling swcs

* bug: removed break

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Co-authored-by: anna-grim <[email protected]>

Author: anna-grim