Gradual progress

Tested the generator system for the tool, which will now seamlessly handle changes in the resource tree while the user is working on it, not like the old one that used a complicated and error prone recursive algorithm to do the same.

Added a valuebar widget to the GUI sys, and started working on the texture generator windows. Texture preview works and the basics are there for the texture parameter window - which is assembled on the fly from the parameters of the texture filter.

I think the texture generator will be completely functional sometime late next week.