Refactor parsing and compiler around List type

[pliniker]

I originally wrote the parser to generate a nested Pair tree data structure, just like Lisp uses cons cells. I did this to simplify bootstrapping into a compiler when I didn't have more complex data structures (like the Array types) available yet.

Since this Lisp-style cons cell data structure is archaic, is it worth refactoring the parser and compiler around the List type?

• the List type is an Array<TaggedCellPtr> so, like most dynamic language arrays is a heterogenous array
• the book chapter(s) on parsing will have to be (re)written around the List type rather than Pairs