It used to mean "Force": it would tell tor-resolve to ask tor to
resolve an address even if it ended with .onion. But when
AutomapHostsOnResolve was added, automatically refusing to resolve
.onion hosts stopped making sense. So in 0.2.1.16-rc (commit
298dc95dfd), we made tor-resolve happy to resolve anything.
The -F option stayed in, though, even though it didn't do anything.
Oddly, it never got documented.
Found while fixing GCC 4.6 "set, unused variable" warnings.
