Provide default support for java.util.Map

```
Should be able to convert the default representation of a Map. 
Should be able to deserialize {{"a":"1"},{"b":2"}} as well as
[{"a":"1"},{"b":2"}] to a map. Consider using a concrete implementation
(linked list) of Map that preserves the order of elements. 
```

Original issue reported on code.google.com by `inder123` on 25 Apr 2008 at 7:16
