[xstream-dev] Support for 'default' collections.

Okay, I've now added basic support for default collections. A default 
collection is a special collection associated with a class that will 
have contain any item that does not map to another field.

Here's an example to make it a bit clearer....

class Person {
   String name;
   List toys;
}

xstream.addDefaultCollection(Person.class, "toys");

<person>
   <name>Joe</name>
   <computer>
       <type>apple</type>
   </computer>
   <car>
       <type>blue</type>
   </car>
</person>

The <name> collection maps to a field in Person, however the other items 
<computer> and <car> don't, so they get added to the 'toys' collection.

Anyone interested in using this, please test it out, so I can iron out 
bugs and edge cases. Sending me bug-reports, failing unit-tests, 
documentation of how to use it or naming suggestions will be appreciated :).

Grab latest snapshot: 
http://dist.codehaus.org/xstream/jars/xstream-SNAPSHOT.jar

-Joe