T19855 Most of the GUI works, except: -changing the mode or data type crashes the API, need to find out why -changing the number of events crashes the API, need to find out why -setting the frequency does nothing as of now

also found out:
-spacing can become zero when changing scanned lines, need to fix that

Signed-off-by: Sattler <sattler@ad.dkfz-heidelberg.de>