* Allow CA clients to determine the server protocol version
Adds a call to the CA client API that allows a client to determine the server's
protocol minor version number. This is needed to allow the ca-nameserver to
report a server's protocol version correctly to a client.
* ca_host_minor_protocol return for disconnected channels
ca_host_minor_protocol now explicitly returns CA_UKN_MINOR_VERSION for a disconnected channel.
In some cases the license-identification header was missing,
so I added that as well. Replaced the remaining headers that
specifically identified "Versions 3.13.7 and higher".
Makefiles and the build system were deliberately excluded.
