@XStreamAsAttribute should support of enum types

@XStreamAsAttribute currently works dont works with enum types, its necessary a specialized converter, the annotation needs the same behavior for enums and object attributes.

Example,

public class Field {
@XStreamAsAttribute
String name;
@XStreamAsAttribute
int bits;
@XStreamAsAttribute
Type type;

// set ang get
}

public enum Type {
TEXT ,
NUMBER;
}

public class TestEnumAttribute {
public static void main(String[] args)

}

Current result:
<fieldname="serial" bits="224">
<type>TEXT</type>
<field>

The new return:
<field name="serial" bits="224" type="TEXT" />