At the moment, this isn't really integrated with the material system; glow-maps are associated with textures, not materials. Being able to specify more detailed things about glow in the material system would probably be useful, but I haven't done that yet.
The material system docs should probably be updated, as should the modeling docs. Also, most of the code I've added has some comments, but could use more, and in general would probably benefit from some cleaning and/or refactoring in places, both for clarity and for optimization. I wouldn't call any of it "production-ready" code at this point, but it should be enough to let people start figuring out what they can do with it, and what needs to be changed/added so the system accomodates their needs better. If you want to document things, be my guest
otherwise, I'm inclined to wait until I'm more confident that the code has stabilized before doing lots of documentation.
Artists, modelers, and mappers; if you'd like to be able to do something related to post-processing and can't figure out how, let me know and I'll see how difficult it would be to add. I welcome feedback about what you do/don't like about the new system; now is the time to comment, while it's still new and flexible.