When posting to "All" or replying to a message that was posted by networked (not local) user, don't attempt to search for that username in the local user base to inform them of the posted message to them.

savemsg() is the underlying C function for saving a new message (mail or post) to a message base from several places, including JS modules. If there was no "charset" specified in the passed message header, check to see if the message body text is non-ASCII but valid UTF-8, and if it is, set the FIDO_CHARSET header field to the appropriate UTF-8 charset identifier string. This would *also* address Issue #177 reported by Michael J. Ryan. It's possible, but unlikely, that a message text would contain valid CP437 that *also* happened to be valid UTF-8. If that does happen to occur (e.g. in posted ANSI art?), we might want to revert this enhancement to savemsg() and leave to the caller's to detect/specify the charset, always.