Start using new AST (avoids checking some syntax in the CESK machine)
Add if and set! to the parser
Fix tags in parser
Don't print tags anymore
Use new AST in CESK
Add higher-order function calls in parser
RPAR missing when parsing define
Other RPAR missing
Add Env.restrict and Env.range, needed to do the abstract GC
Update README
Add free_variables
Add test for free_variables
Parse letrec, remove define
Remove references to define, rename some stuff
Handle letrec in the CESK machine
Fix AST tests
Fix simple tests
Fix advanced tests
Compute live locations
Add gc