I don't think this commit works or even compiles, I have too many
changes and I have to start committing from somewhere. At the same
time I don't want to make a "lots of changes here and there" kind
of commit.
Lots of changes I made on the train and had little
time to make tidily.
Use c++17 (for std::optional)
Clean up the cmake script a bit
Get rid of unused stuff
Skeleton implementation of some classes for scraplang
