Bug 145021 Enhance the agrregate on option in column binding dialog
1. Check if the expression is aggregate expression by data utility class. 2. If yes, the option is ?all? and group name list 3. if not, the option disabled (or set to none?) if the column binding is in detail row. If the column binding is in group row, the option is ?None? and group name list.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/util/DataUtil.java
{
			DataSetUIUtil.updateColumnCache( handle );
			meta = handle.getCachedMetaDataHandle( );
		}
		MemberHandle resultSet = meta.getResultSet( );
		List result = new ArrayList( );
		if ( resultSet.getListValue( ) != null )
		{
			for ( int i = 0; i < resultSet.getListValue( ).size( ); i++ )
			{
				result.add( resultSet.getAt( i ) );
			}
		}
		return result;
	}
	/**
	 * Generate computed columns for the given report item with the closest data
	 * set available.
	 * 
	 * @param handle
	 *            the handle of the report item
	 * 
	 * @return true if succeed,or fail if no column generated.
	 */
	public static List generateComputedColumns( ReportItemHandle handle )
			throws SemanticException
	{
		Assert.isNotNull( handle );
		DataSetHandle dataSetHandle = handle.getDataSet( );
		if ( dataSetHandle == null )