found a complete archive of SSLeay-0.4 to SSLeay-0.8.1b tarballs
on the web, so fix up SSLeay HISTORY accordingly

err.h HISTORY up to SSLeay 0.8.1b; researched from OpenSSL git

Add Copyright and license.
Garbage collect the empty RETURN VALUES section.

first pass; ok schwarze

convert ERR manuals from pod to mdoc; while reading this,
i wtfed, laughed, puked, and cried in more or less that order...