+/**
+Command line option processor. Both short and long options are supported, with
+optional and required arguments. Automatic help text generation is also
+available.
+
+Short options begin with a single dash and are identified by a single letter.
+Multiple short options may be grouped if they take no arguments; for example,
+the string "-abc" could be interpreted as having the options 'a', 'b' and 'c'.
+If the option takes an argument and there are unused characters in the argv
+element, then those characters are interpreted as the argument. Otherwise the
+next element is taken as the argument. An optional argument must be given in
+the same element.
+
+Long options begin with a double dash and are identified by an arbitrary
+string. An argument can be specified either in the same argv element,
+separated by an equals sign, or in the next element. As with short options,
+an optional argument must be in the same element.
+
+A single option may have both alternative forms, but must always have at least
+a long form. This is to encourage self-documenting options; it's much easier
+to remember words than letters.
+
+A built-in --help option is provided and will output a list of options and
+their associated help texts. An application may override this by providing
+its own option with the same name.
+*/