New Magic tool: Color Sep. (aka 3D Glasses)

docs/CHANGES.txt

@@ -7,7 +7,7 @@ Various contributors (see below, and AUTHORS.txt)
 https://tuxpaint.org/
 
 
-2023.February.19 (0.9.29)
+2023.February.21 (0.9.29)
   * Improvements to "Stamp" tool:
     -----------------------------
     * Stamps may now be rotated.
@@ -48,6 +48,12 @@ https://tuxpaint.org/
       (Sound effected licensed as Creative Commons 0 (CC0 1.0)
       by https://freesound.org/people/kentnelson64/)
 
+    * "Color Sep." (color separation) - Separate the colors of the
+      image, e.g. Red vs Cyan, as in anaglyphic "3D glasses" images.
+      Bill Kendrick <bill@newbreedsoftware.com>
+      (Sound effected licensed as Creative Commons 0 (CC0 1.0)
+      by https://freesound.org/people/Zarkonnen/)
+
     * [WIP] "Rivulet"; apply rivulets of water to the canvas
       - needs better icon
       - needs sound effect