1. I don't know how to get said script to run. Something is not really working right(I don't have any startup.lua and even when I create it I don't see any changes). And I really didn't see any possibility for pattern matching in the script.
2. Why not add this functionality natively to the program, just like the "Ignore users" field in the "Misc" category, only it should be "Ignore messages". I can see by the checkbox in that very same field that there is already a regex engine implemented, so it should really be fairly trivial to add.