It is now possible to use a signed key file with AWS. In this case
a pass-phrase is requested to be able to start the HTTPS
session. This pass-phrase can be handed over to the server using
the Set_Password_Callback in AWS.Net.SSL.Certificate.
The HTTPS demo has been enhanced to demonstrate this.
Add corresponding regression test.
For 0202-018.
When the priority string is empty it is set depending on the
protocol version set in Security_Mode. This allows better
compatibility with the OpenSSL mode.
Motivated by O202-018.