ref: c5110102ce2df2d78a0c87f293edf20f5a3984e7 scheme-vm/spec d---------
Add more char functions
Add case insensitive char comparision functions
Improve lib spec failure message
Support all character names in the spec
Add string->symbol function
Add symbol->string and symbol=? functions
Allow comparing more than 2 strings with string=?
Get rid of unneeded keep_last option

`keep_last: true` was only being used by specs, and `(exit)`
already accomplishes the same effect, leaving the stack intact for
Fix error when it's on line 1
Show better message on syntax error
Fix parser bug

(foo)(bar) could not be parsed
Store line and column number for better errors
Fix bug compiling an empty list
Deep dup AST until I can figure out the bug

There is a use-after-free error I believe.
Hook Rust parser into Ruby

I have a bunch of failing tests, so I've focused the parser test for now.
Move specs to proper file
Add make-list function
Update watchr script to only run relevant specs
Fix string->number for negative numbers
Implement string->number for positive numbers