fixing multilogger so that v is properly nil instead of an empty slice if not specified

logging/doc.go

@@ -11,6 +11,10 @@ These particular loggers (logging.Logger) available are:
 
 There is a sixth type of logging.Logger, MultiLogger, that allows for multiple loggers to be written to with a single call.
 
+Note that for some Loggers, the prefix may be modified - "literal" loggers (StdLogger and FileLogger) will append a space to the end of the prefix.
+If this is undesired (unlikely), you will need to modify (Logger).Prefix and run (Logger).Logger.SetPrefix(yourPrefixHere) for the respective logger.
+
+
 Every logging.Logger type has the following methods that correspond to certain "levels".
 
 	Alert(s string, v ...interface{}) (err error)