Tail call elimination
Refactor special forms into fexprs
Escape html
Change representation of functions and specials
Convert cond to fexpr as well
Get rid of couple of console.log calls
Localize recursive evaluation
Localize simple part of eval
Rename expr -> exp everywhere
Extract testing framework into separate file
Externalize stack
Move REPL into a separate file
Make cond use the externalized stack
Change write to distinguish eval'ed callables
Refactor eval