Bug 185931 Support to distinguish the week between Year-Week and Month-Week[1101]
Description: In our OLAP builder, the datetime dimension is divided into YEAR-QUARTER-MONTH-WEEK-DAY. When select all the levels, the WEEK should be the week(1 to 5) in one MONTH When select YEAR-WEEK levels, the WEEK should be the week(1 to 52) in one YEAR But now in our OLAP builder, the WEEK only belong to the MONTH, But not belong to the year, so if only select the YEAR-WEEK level, the result of crosstab is meaningless. The YEAR-DAY, MONTH-DAY and WEEK-DAY also have the same issues. we should define a rule to make sure the WEEK has a correct relationship of his parent
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ModuleHandle.java
* @return A handle for working with the data sources.
	 */
	public SlotHandle getDataSources( )
	{
		return getSlot( DATA_SOURCE_SLOT );
	}
	/**
	 * Returns the default units for the design. These are the units that are
	 * used for dimensions that don't explicitly specify units.
	 * 
	 * @return the default units for the design.
	 * @see org.eclipse.birt.report.model.api.metadata.DimensionValue
	 */
	public String getDefaultUnits( )
	{
		return module.getUnits( );
	}
	/**
	 * Sets the default units for the design. These are the units that are used
	 * for dimensions that don't explicitly specify units.
	 * <p>
	 * 
	 * For a report design, it allows the following constants that defined in
	 * <code>{@link org.eclipse.birt.report.model.api.elements.DesignChoiceConstants}</code>:
	 * <ul>
	 * <li><code>UNITS_IN</code></li>
	 * <li><code>UNITS_CM</code></li>
	 * <li><code>UNITS_MM</code></li>
	 * <li><code>UNITS_PT</code></li>
	 * </ul>