Alpha Channel in Emblem Editor

Not much happened today, but I did manage to get the emblem editor to respect the alpha values of the source images. It now also provides an alpha threshold slider to configure how it interprets the alpha values of the image. It still does not support alpha dithering, though this is probably not that useful in the long run. If I'm wrong, it can come later. For now, though, I think the emblem editor is pretty much done to my satisfaction.