Some various fixes:

* Makes it possibly to set the point labels and tool-tips in the charts via the chart descriptor
* Removes a NPE when selections are made in the chart
* Removes two unused radio-buttons from the ChartDialog
* Adds "plot column" to the pop-up menu of sdf-editors column header
* Removes some unused and unnecessary code
* Makes the name change from *UiManager to *ChartManager