Bug 136279 Structure and table datatypes should be hidden.
Description: Structure and table datatype should be hidden. Steps to reproduce: In table data binding, I saw structure and table two datatypes. They are not supported now, so they should be removed.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/adapter/ModelDteApiAdapter.java
if ( dataSource instanceof ScriptDataSourceHandle )
			return newScriptDataSource( ( ScriptDataSourceHandle ) dataSource );
		
		assert false;
		return null;
	}
	/**
	 * Adapts the specified Model Data Set to a Data Engine API data set design
	 * object
	 */
	public IBaseDataSetDesign createDataSetDesign( DataSetHandle dataSet )
			throws BirtException
	{
		if ( dataSet instanceof OdaDataSetHandle )
			return newOdaDataSet( ( OdaDataSetHandle ) dataSet,
					context );
		if ( dataSet instanceof ScriptDataSetHandle )
			return newScriptDataSet( ( ScriptDataSetHandle ) dataSet,
					context );
		
		if ( dataSet instanceof JointDataSetHandle )
			return newJointDataSet( (JointDataSetHandle)dataSet, context);
		
		assert false;
		return null;
	}
	/**
	 * Create an IJointDataSetDesign instance.
	 * 
	 * @param handle