win32 is not a supported platform; remove remaining incidental mentions of it

The mention of Win32::Locale::Lexicon remains, because
I18N::LangTags::Detect version 1.04 and below (i.e. perl prior to
5.14.0) generates "used only once" warnings without it.
Remove mention of IIS, which RT does not run under
mod_auth_pwcheck was Apache 1.3 only; replace with Apache 2.x equivalent

This serves to further point out the $WebRemoteUserGecos is quite
possibly unused and unnecessary.
Merge branch '4.2/remove-win32' into 4.2-trunk