Substantially improved variable nomenclature.

In particular, renamed "_string_integer" to "_integer" everywhere.
Documented initial thoughts on metadata retrieval from binary files.
Eliminated the prior "if_theme"-based filesystem theme system in favor
of a zsh function-based dynamic theme system. While the latter has yet
to be fully realized, it's shaping up in the elided eye of my mind's
tattered frays to be quite something.