Bug 150347 Support binary stream as preview image.
See 144843. We need model to save binary strame as report preview image. Currently, preview image is an external image. Maybe need a type to distinguish preview image type.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/NameSpaceRecord.java
* @param isAdd
	 *            whether to add (true) or remove (false) the element.
	 */
	public NameSpaceRecord( Module theRoot, int ns, DesignElement symbol,
			boolean isAdd )
	{
		root = theRoot;
		element = symbol;
		nameSpaceID = ns;
		add = isAdd;
		assert root != null;
		assert element != null;
		
		
		
		if ( add )
			label = ModelMessages
					.getMessage( MessageConstants.INSERT_ELEMENT_MESSAGE );
		else
			label = ModelMessages
					.getMessage( MessageConstants.DELETE_ELEMENT_MESSAGE );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.design.core.SimpleRecord#perform(boolean)
	 */
	protected void perform( boolean undo )
	{
		NameSpace ns = root.getNameSpace( nameSpaceID );