PreFtpCommands: send some server-specific commands to the ftp-server

This feature should be used to send commands to a ftp-server, which are not implemented in SOSFtp or SOSDEx directly.

Example:

Pre_Ftp_Commands=OPTS UTF8 ON

More than one command must be delimted by a ";".

The command(s) will be send to the server after establish the connection and authorisation and before sending the first commands (e.g. change dir, get/put files etc.).