Tool to replace all pixels of one color with another color

[FireFist-Redhawk]

This would be very beneficial for pixel manipulation on icons with many layers. I envision this being in the Tools menu of the editor. A dialog would come up that has one color box control for the color to be replaced and another for the replacement color. When the color to be replaced is changed, perhaps a message underneath could tell the user that the color is present on X pixels of X layers. Lastly there would of course be a Replace button and a Cancel button to proceed or exit the dialog.