Added new putmsg()/printfile() mode flag: P_UTF8

Set automatically when printing a *.utf8 file or a file starting with ZWNBSP
(BOM) UTF-8 sequence.
When set, UTF-8 sequences will be converted to a compatible charset for the
user's terminal.

exec/load/sbbsdefs.js

@@ -225,7 +225,7 @@ var   P_TRUNCATE    =(1<<9);    /* Truncate (don't display) long lines      */
 var   P_NOERROR     =(1<<10);   /* Don't report error if file doesn't exist */
 var   P_PETSCII     =(1<<11);   /* Message is native PETSCII                */
 var   P_WRAP        =(1<<12);   /* Wrap/split long-lines, ungracefully      */
-
+var   P_UTF8        =(1<<13);	/* Message is UTF-8 encoded                 */
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