Subsubcommand 4 - Send a message to all party members

Client message:

Subsubcommand 4: Tell full party a message (Variable # of bytes)
BYTE[n][2] Null terminated Unicode message.

Server message:

Subsubcommand 4: Tell full party a message (Variable # of bytes)
BYTE[4] id (of source)
BYTE[n][2] Null terminated Unicode message.