menu: created tailmenu

Made donate, sponsors and web site info into its own little "tail menu"
under ther regular left side main menu instead of the previously
distributed manner they had various links. Made the tailmenu a slightly
different colour.

Removed the change date from the bottom of the page. Added a <hr> at the
end before the end-of-page ad.

Made most menus and makefiles use sflogo.t directly instead of the .html
version as that gives an additional redirection that's annoying in makefiles
and dependencies.
about: slightly refreshed
foot: remove analytics leftovers
sponsor: clarify what a sponsor really is
Makefile: removed superfluous dependency
css: made "tabletop" less intense
mail: make a single table, removed dead lists, add spacing
perl: remove references to old web directoy
menus: unified LINK/VLINK usage in _menu.html files
mail: list only the recent 4 years by defaulr