added getter and setter for propertygrid
Merge remote-tracking branch 'origin/master' into PropetyGrid
Added event for elements
Changed some tags in AbstractMarker, AbstractTrackable, IDMarker, PictureMarker

Deleted similarityThreshold in PictureMarker, becaus it is already in AbstractTrackable
Added FileSelectorTypeEditor for openFileDialog when changing image of image Marker
Merge remote-tracking branch 'origin/master' into PropetyGrid
Added event to move elements in the previewPanel

Added/changed some tags in BarGraph, Graph
Added default construktor in PictureMarker
Merge remote-tracking branch 'origin/master' into PropetyGrid

Conflicts:
	Editor/Controller/EditorController/PreviewController.cs
Merge remote-tracking branch 'origin/master' into PropetyGrid
unnecessary...