Review and anonymous-ize nested subs

[Kris Deugau]

See eg ​https://www.perlmonks.org/bare/?node_id=137292 and ​https://stackoverflow.com/questions/4048248/variable-foo-will-not-stay-shared-warning-error-in-perl-while-calling-subrout, and a live instance of this error fixed in r804.

Nested subs are, more or less, technically just subs that happen to have been defined inside another sub, and as such have limited (and potentially buggy) access to their nominal parent's local variables.

Review each one in detail to ensure clear data passing and caller scope. Optionally convert to anonymous subs Just To Make Sure.