Hmpf. I don't think I am in violation much. I did not copy any code Not really anyways.
Well, I can't copy paste C++ to C# code. Plus I argue the point of code in general, which is basically used to implement an algorithm and the algorithm, specifically the person command-queue must be made compliant so things like Lord English's Scenario work between my engine and Vanilla Sphere's. So while I say I "took code" I really just copied an algorithm. If Valve wants to get into a legal dispute with me I'd say let them. Because I'd also like to put their API into my engine. The GPL doesn't or at least shouldn't cover "ideas" like the person command queue. I'd wager, unless you have solid copy-paste proof (ex: revealing comments were copied over), I'd say it's nearly impossible to tell.