Tables with a file name are: any game state, and any table that's
initialized from a .config file.
Tables that are no longer customizable: "updates" (customization had
no effect, because update_get_schedule() overwrote it), "table",
"meta" and the symbol tables (customization couldn't change them
anyway), and news-chr (customizing r_newsstory[] was kind of neat, but
unsafe because they are format strings for sprintf()).