Make it possible to choose encoding preference for server
The server encoding preference can now be customized with QT_VNCSERVER_PREFERRED_ENCODING environment variable. Set this to a semi-colon-separated list of encodings. The first that is supported by the client will be picked. If none are supported by the client, the client's first supported preference will be chosen instead. E.g.: QT_VNCSERVER_PREFERRED_ENCODING=hextile;zlib This would make the server prefer hextile over zlib, even if the client prefers zlib.