Issue #403: Update Color Dialog page
This patch attempts to resolve issue #403.
It updates the Color Dialog images. It also makes the following text changes:
- Rename the "Triangle" to "Wheel" per GIMP label
- Swap the order of "Wheel" and "Watercolor" per their placement in 2.99
- Add additional details about CMYK and Lch options.
Feedback and additional changes are welcome!