Second round of fixing the OpenSSL perl/ stuff. It now at least compiled fine

under Unix and passes some trivial tests I've now added. But the whole stuff
is horribly incomplete, so a README.1ST with a disclaimer was added to make
sure no one expects that this stuff really works in the OpenSSL 0.9.2 release.
Additionally I've started to clean the XS sources up and fixed a few little
bugs and inconsistencies in OpenSSL.{pm,xs} and openssl_bio.xs.

PS: I'm still not convinces whether we should try to make this
    finally running or kick it out and replace it with some
    other module....