Bug 189706 Enhance computed column aggregation function handling in UI.
Due to the issue discussed in 189705, current computed column aggregation builder in data set editor has bugs to extend: 1.When new a computed column, the aggregation argument field cannot be correctly set. 2.The argument field cannot be correct grayed out when user select a aggregation function without arguments 3.The available aggregation function list is incomprehensive 4.Some aggregation function cannot be set to model(say, weightedAve).
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/ComputedColumnHelper.java
* @return
	 */
	private List getComputedNameList( List dataSetCCList )
	{
		List result = new ArrayList( );
		for ( int i = 0; i < dataSetCCList.size( ); i++ )
		{
			IComputedColumn column = (IComputedColumn) dataSetCCList.get( i );
			result.add( column.getName( ) );
		}
		return result;
	}	
	/**
	 * 
	 * @param dataSetCCList
	 * @return
	 * @throws DataException 
	 */
	private void getAvailableComputedList( List refernceNameList,
			List dataSetCCList, List result ) throws DataException
	{
		try
		{
			for ( int i = 0; i < dataSetCCList.size( ); i++ )
			{
				IComputedColumn column = (IComputedColumn) dataSetCCList.get( i );
				if ( !refernceNameList.contains( column.getName( ) ) )
				{
					continue;
				}