Improving the doc
fixed up the code. Now I feel a little better.
Fix ARGS4J-25 - support args like "-coll val1 val2 -coll val3" with `@Option(handler = StringArrayOptionHandler.class, …)`

Fix `java.lang.IllegalArgumentException: array element type mismatch`
Revisted ARGS4J-25 patch.

StringArrayOptionHandler shouldn't batch up tokens into a single array and use Setter<String[]>.
The Setter abstraction is designed to work with individual items, in this case String.
See RestOfArgumentsHandler as an example.

With this change, the modification in ArrayFieldSetter made in the previous commit becomes unnecessary.
doc clarification