Returns an int specifying the number of times that the flag was
specified on the command line. Once this flag is looked for you
must save the result because if you call it again for the same
flag you'll get zero.
Returns a string (or null) specifying the value for the passed
option. If the option isn't there then null is returned. The
option's value can be specified one of two ways:
Note that: -ax value
is not value (meaning flag 'a' followed by option 'x'.
Options with values must be the first char after the '-'.
If the option is specified more than once then the last one wins.