Cake static analysis for C: ownership, nullability and initialization

It's been about 10 months since I posted about Cake's ownership and nullability model.

Since then, I've significantly improved Cake's flow analysis.

The new analysis can track the origins of states across control-flow paths, making it easier to understand where a state came from and how it reached a particular point in the program.

Another milestone is that the entire Cake source code is now annotated with ownership and nullability, and checked by Cake itself.

I've documented the flow analysis here:

https://cakecc.org/flow.html