Go back to the HashMap of ViewId and Calibration/Dimension as it is
defined like this in the ImgLoader, and it makes sense. However, we
change the getImageSize() and getVoxelSize() calls to look for the same
ViewSetup of other Timepoints to potentially return the calibration.
Otherwise, many different files will be opened to get the same data.
Still not sure if this is the right thing to do.