Building an incremental sysimage in seconds instead of minutes

This is a research project. I’m putting it out so that others can experiment with it. You have to build both branches from source. Some background on why I did this. I’m writing a discrete event network simulator in Julia. People write their simulation models on top of it, and not everyone wants to work in the REPL. If someone prefers to run a compiled binary instead, I don’t want to prevent that and lose a customer. The problem was that create_app took two and a half minutes for every source c...