By default, '-l' (last few callers) option will pull from previous days

If modopts.ini [logonlist] last_few_days is set (to a number), that will
dictate the maximum number of previous days to pull last few callers from
(e.g. set to '0' for previous behavior).

Also, '-l' can now be used with a command-line option (e.g. '-l <num>')
to specify the number of callers to display (overriding the modopts.ini
last_fwe_callers value).

This should address issue (feature request) #371.