Add support for properly aligning options with and without short and long names in show-option-help.

Instead of having

-f --foo
--bar

Now we have

-f --foo
   --bar

when bar specifies #\Space as the short option designator.

New lines are still supported. Set *print-right-margin* to control where
word wrapping occurs. To provide a sensible default it cannot be smaller than 100.
Update test case.

Format multiline documentation properly indented,
that is each line should start at the same column.
Print option type too and use little bit wider tabs.

Also, show default value in help.
Feature requested by Levente Mészáros.
Additionally bug fix by Levente whereby we show help correctly
when a name, not a list of names, is provided.

XCVB itself imported a version from ITA's QUUX in early 2009, and modified it.