Bug 134954 Library can't be removed
Steps to reproduce: 1.New a report "a.rptdesign" 2.New a library which is not in the same fold with report, saying "../test/lib.rptlibrary" 3.Report includes the library 4.Remove the library Expected result: The library is removed Actual result: Open XMLSource, the included library structure is still there.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/LibraryCommand.java
command.remove( tmpElement, tmpElement.getContainerSlot( ), false,
					true );
		}
		
		parent.dropDerived( child );
		value.unresolved( value.getName( ) );
		return overriddenValues;
	}
	/**
	 * Recursively collect all the descendents of the given element.
	 * 
	 * @param element
	 *            a given element.
	 * @param results
	 *            the result list containing all the childs.
	 */
	private void getAllDescdents( DesignElement element, List results )
	{
		List descends = element.getDerived( );
		results.addAll( descends );
		for ( int i = 0; i < descends.size( ); i++ )
		{
			getAllDescdents( (DesignElement) descends.get( i ), results );
		}
	}
	/**
	 * drop the include library structure.
	 * 
	 * @param fileName
	 *            file name of the library.