Squeasel does not allow the SSL certificate and private key to live in separate files:
(Note that pem is the same file in both SSL_CTX_... calls).
We should improve it to allow two options, one for the private key and one for the certificate. For backwards compatibility reasons, we should default to the same file if only one file is given.
While we're here, we should allow the client of the Squeasel library to provide a callback for giving a password for the private key (see also