* zic.8, zoneinfo2tdf.pl: Change names of Link line fields to be more
descriptive and more like the parameters of 'ln'. LINK-FROM becomes
TARGET, and LINK-TO becomes LINK-NAME.
* backward: Add a '# Link' header.
* europe, northamerica: Add a few '# Zone' headers where needed.
* NEWS: Document this.
Most of this patch is to commentary, to distinguish better among
the similar characters hyphen '-', minus sign '−', en dash '–' (used
for ranges), and em dash '—'. Render ordinary dashes in text as
spaced en dashes, as this gives better-looking results in monospaced
fonts.
* yearistype.sh, zic.c: Reword diagnostics so that they do not use
hyphens as if they were dashes. Since we are sticking to ASCII in
programs, we can't use proper dashes in diagnostics.
