Helper function for count_within_batch and count_within_many. This does the actual work of calling count_within multiple times and accumulating the result.

count_within_many_impl(csd, name, combos, radii, phenotype_rules)

## Arguments

csd Cell seg data for a single field. Name associated with csd, for example the basename of the image file. List of pairs of (from phenotype name, to phenotype name) and tissue category. Vector of radii. Named list of phenotype rules.