cantora

As a preliminary test, I tried modifying the `free-vars` function to return `empty-stringset` for all inputs. This of course causes cedille to report errors when it tries to check stdlib.ced....

Also, I noticed that many different parts of Cedille (outside of classify) use the free-var functions. Did we want to only focus on improving the free-var logic for classify? Or...

I added a module parameter disable the `free-vars` function with the free-vars module. This allowed me to locally disable this function in the various modules that use the free-vars module....