Creates a shining glow as demonstrated in the tutorial here: http://www.gimpusers.com/tutorials/rays-of-light-behind-text.html
This script will only operate on the alpha-layer
It assumes that the layer size is the same size as the image size
It will not add color to the rays as in the tutorial
The rays are now created much like an outer glow, rather than being merged with a background as in the tutorial
Tested in v2.4.2 only
This script allows you to extract and apply saturation to a layer. When you extract, it adds a new layer with the saturation values (in gray colors). You can then use curves, brightness/contrast or the dodge tool to correct saturation. When you are okay with the adjustements you can put back the saturation by applying it.