multiscreen wallpaper does not support different bg mode

[tsankuanglee]

I was able to run this and put different images on different screens: feh --bg-max 1.png --bg-fill 2.png --bg-center 3.png However, all of them are applied --bg-center

Right now I just tweak my original image sizes for this to work, but it'd be nice to if it worked as expected.

[avlec]

As it currently stands when evoked feh will only ever enter 1 background mode. So essentially the --bg-max and --bg-fill are ignored. The image list you provide is preserved though, as for each "screen" feh will use one of the images provided, and this order is dependent on the order Xinerama has the screens in. I am working on implimenting #590 and I will look into other background modes. The only thing that would change would be instead of 1 call, you'd have 3 seperate calls, each specifying which Xinerama screen they're targeting (see xinerama-index option) or if Xinerama is not being used it might be useful to use the geometry option on the "full modes" for specifying the size and positions of the "screens".