Aggregation is disabled in charting #856

[claesrosell]

Enabled aggregation again. Seems to have been a negation wrong after refactoring. Also expanded
the default IChartUIHelper.useDataSetRow() implementation to a simple startsWith("data") check previously used in the enableAddEditor() method

[claesrosell]

The change in ChartUIHelperBase.useDataSetRow(Object reportItem, String expression) is taken from the old test used in the BaseDataDefinitionComponent.enableAggEditor() prior to the refactoring done in commit b40bee0 , however the useDataSetRow() method is now used in other places as well and may effect those. According to the javadoc the method should:
"Return true if expression uses binding that contains data set row directly or indirectly"
but did only return "false" in the only implementation.
I think that this is a minimal start for a useDataSetRow() implementation, we can expand on it in the future when our knowledge of the code base has increased.

[claesrosell]

qs-wang Can you provide any input on this? I got the feeling that you have worked on Birt previously.

[wimjongman]

Claes, we have to close master until we have released 4.9. I am fine taking this in but you have to do it now.

Otherwise, we retarget this for 4.10