[DCP-o-matic] DCP naming recommendation

Not sure if DOM already respects this, but if really some systems counts the underscores, may be worth a look. It's from the ISDCF list. "There MUST be an entry in EVERY field. Some systems count the number of "_" (underscores) to parse the information (NOT RECOMMENDED - BUT it's done). If you have a non- relevant field, fill it with the letters "NULL" This may explain all the naming errors we get from dcp_inspect that are not really errors. Manuel AC