Add CoreImage filter to fade tiles out slightly

[tomtaylor]

To make it easier to still see what's on the desktop.

[bobthecow]

I made Vibrant Haze for just this reason.

Also, I couldn't get a "lighten" filter working for both Bing and non-Bing. At least in SF, Bing's too wildly different to use the same effect presets as the rest of the maps.

[tomtaylor]

Ah, right. I guess we could special case some of the filter variables, maybe just for Bing?

[OldhamMade]

I'd like to see this also; I use GeekTool to show a lot of changing data on my desktop. Being able to adjust the transparency of the map image, or add a colour overlay, would help provide a better contrast for the text.

[klihelp]

+1, because can't read the desctop items' title