BitsPlusPlus: Handle Apple macOS Retina displays properly for imaging…

… pipeline validation runs.

Obviously meaningless for normal use with standard DPI CRS and VPixx devices, but needed
for imaging pipeline validation on Apple Retina machines.

Psychtoolbox/PsychGLImageProcessing/BitsPlusPlus.m

@@ -1287,7 +1287,7 @@
     end
 
     % Imagingmode must at least include the following:
-    imagingmode = mor(imagingmode, kPsychNeedFastBackingStore, kPsychNeedOutputConversion, ourspec);
+    imagingmode = mor(imagingmode, kPsychNeedFastBackingStore, kPsychNeedOutputConversion, kPsychNeedRetinaResolution, ourspec);
 
     if strcmpi(cmd, 'OpenWindowColor++')
         if isempty(colorConversionMode)