ssl peer verify fixes and more

CURLE_SSL_PEER_CERTIFICATE is added

code for peer certificate errors

already been transfered no longer returns error but instead is OK. The
reasoning behind this is of course that no extra actions need to be taken
and it is as if a transfer had been successfully performed.

strnequal() approach that really didn't follow the RFC properly

that multiple FTP transfers were not possible

SIZE doesn't work, we just don't output any size info!

connections.