Fix update issue.

Preliminary fix issue in previous commit.

Problem: Bit depth is set in inherited class which is actually not known
here....
Partly closes #15.

Closes #106

Add LV unit to Simulation/Rotation property.

This should now be handled by the application code (e.g. CamActor).

This eliminates the dependency between ImgSrcConfig and ImgSrcGUI

if the window was hidden/minimized before.