ColortableLayer: When generating random colors, accept flag for zeroIsTransparent.
layerstack: Clear selection before selecting a new row (to avoid errors caused by multiple selected rows)
widgets: export options: When format selection is invalid, show the error message from the export operator.
Viewer: Fix RGBA channel index count.
imagesources: GrayscaleImageRequest: Truncate 64-bit integers before display to avoid a crash.
Emit a warning because it isn't correct behavior, but it's still better than crashing...
imagesources: GrayscaleImageRequest: Copy input array if necessary before passing to gray2qimage_ARGB32Premultiplied()