added format to allow download of float16 images, PixImage must be allocated manually of type float16 and passed to Download since there is no creator for this type;
added format to allow download of float16 images, PixImage must be allocated manually of type float16 and passed to Download since there is no creator for this type;

vrvis/aardvark.rendering,vrvis/aardvark.rendering,vrvis/aardvark.rendering,vrvis/aardvark.rendering