only display saved pie chart if the dataset has this column
Merge branch 'origin/piechart'
BugFix: correct optgroup boundaries (although date,lat,lon will be "magically" added to the last optgroup)
BugFix: keep correct names for TimeSpans, so that they will be correct later on export
Merge branch 'DataLoadingUI'
Timespan information is now real part of table content
Merge branch 'exportDataset'

Conflicts:
	js/GeoTemConfig.js
Merge branch 'origin/piechart'
Merge branch 'origin/master'