Added macro definitions for max branches and time-slice yield frequency.

Moved JS-related constant definitions to sbbsdefs.h.

Added special log output to ftp_close_socket when closing the server socket.
Rearranged termination sequence at end of ctrl_thread to fix race conditions.
Added wait at end of ftp_server thread for other threads to terminate

Added "To:" field to outbound messages and now imports "To:" fields, if specified.

the valid size of the user.dat, generates an error log message, and fixes the
user number so the record can be created successfully.

Removed tagline from imported messages (no purpose).
Updated default tagline format.

using dynamically allocated xfer_t buffer rather than static local variable.

Uses IHAVE command to post exported messages.

Added extra bool param to get_msg_body method (tails).
Created get_msg_tail() method.

Posted messages now use original date/time in header.