Simplest REPL
Add mpc lib for parsing
Change AST into values
Noddy functions and application
Lambdas, and envs
Use cons instead of sexpr and add vectors

This will get hairier before it gets smoother.
Use vectors for environments

Fewer kinds of thing = less complication. Cute encoding due to Tony.
Use header for vals, and inline closures
Give objects different types, and do our own allocation

Well, wrap malloc, but this paves the way for a garbage collector.
Tests

(also needed lispy to accept expressions on the command line)
Stop-and-copy collector

Using Cheney's algorithm. Probably doesn't work properly.
Add strings
Ignore
Use cc rather than gcc