update: cmd_pre now uses options['instance'] to set the server hostname instead of assuming localhost; two environment variables, VIRTUOSO_BIN and INSTANCEFILE, are now being used to specify the absolute path to the isql binary (conflicts with linux/unix 

update: cmd_pre now uses options['instance'] to set the server hostname instead of assuming localhost; two environment variables, VIRTUOSO_BIN and INSTANCEFILE, are now being used to specify the absolute path to the isql binary (conflicts with linux/unix oracle client, and the instance file, which contains the port information