Added scfg_t* argument to sbbs_write_ini().

Passing a NULL hostname to sbbs_get_ini_fname() now automatically uses
gethostname() (and the proper WinSock init/cleanup) to get the hostname.
read_ini_globals() no longer clears the global.ctrl_dir, temp_dir, and
host_name elements if they're not specified in the .ini file.
Option bits are now separated by " | " instead of just "|".