Remove visibility checkbox from models
Reason: The checkboxes can lead to the follwing problems
- Users could wrongly assume this is an interaction element and try to click on it/getting confused.
- The state might not be valid, because only the general visiblity is shown. This might not be the case for specific render windows. Better use the rendering manager to convey the visiblity information.
Signed-off-by: Ralf Floca <r.floca@dkfz-heidelberg.de>