JS_THREADSAFE is now defined in sbbs.h - this change requires a cvs update in

the include directory to get the new include/mozilla/nspr header files
(or js_internal.c will fail to compile)!
savemsg() now uses smb_addmsg() for most of it's functionality.
savemsg() now accepts an optional client_t* argument, if non-NULL will
automatically call msg_client_hfields().
MsgBase.save_msg() method now accepts an optional client object argument to
automatically set the security log header fields (sender IP addres, hostname,
protocol, and port).