sendDirectMessage
Sends a direct message from one player to another on the same server. Handles formatting, and applies romaji-to-Japanese conversion if sender has it enabled.
The conversation is recorded by the caller via recordMessage before the delivery is queued, for the same reason as recordRemoteRecipient. Recording it here as well would also re-insert entries that clearPlayer has already swept, if the recipient quits mid-delivery.
Return
true if message was sent successfully