Adds a tape machine way of executing the code. The tape machine is a series of FunctionCall objects, which can either be called one by one, or be used to generate expressions to make up a function. Reviewed-on: Rubydragon/MetagraphOptimization.jl#30 Co-authored-by: Anton Reinhard <anton.reinhard@proton.me> Co-committed-by: Anton Reinhard <anton.reinhard@proton.me>