Bug 130492 Provide a method to serialize the report with library information.
Currently, when engine generate the report document file, the document does not contain any library information. That will cause many propblem on server side. Model should provide a method to serialize the report with library information to a stream so that the generated report document can contain all information that the report need.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
* <dd>Inheritance only works between elements of the same type. One could say
 * that a derived element inherits the element type of the parent element. More
 * precisely, both the parent and derived elements have a type, and the
 * semantics of the application require that the element types be the same. It
 * is an error to extend an element of a different type.</dd>
 * 
 * <dt><strong>User-defined properties </strong></dt>
 * <dd>The user can define a custom property. All derived elements also have
 * that property.</dd>
 * 
 * <dt><strong>Custom behavior </strong></dt>
 * <dd>The user can define custom behavior by associating the element with a
 * Java class. Derived elements inherit this behavior.</dd>
 * </dl>
 * <p>
 * 
 * Inheritance does <em>not</em>, however, apply to the following:
 * <p>
 * <ul>
 * <li><strong>Name </strong>. A derived element does not inherit the name of
 * the parent component. If it did, then there would be two elements with the
 * same name, violating the rules about element name uniqueness.</li>
 * 
 * <li><strong>Parent element </strong>. A derived element necessarily has a
 * distinct value for the "extends" property than does its parent.</li>
 * </ul>
 * <p>
 * 
 * Members and classes in the inheritance system include:
 * <p>