Reconfigure the top-level object types.
- Obj is an enum pointer type
- Object is a trait that all Scheme types should implement
Define Sym, a symbol type.
Define Pair, a pair/cons/list type.
Implement Display for all types above. Implement casting methods for the above.
- Comment out a bunch of types modules for now
- Implement fmt::Display on Object (this breaks the build because Number doesn't
implement Display yet)
- Move all the Is* traits to predicates.rs
Haven't run tests yet because they won't build...
