First draft of DeBruijn indices and substitution
Fixed name-capture bug in type-checking
Use `putUtf8` helper function
Removed trailing whitespace
Updated tutorial to reflect changes to indexing
Removed wasteful double-normalize
Removed space leaks
Updated documentation
Removed strictness annotation from `Var`
Polished source code
Fixed eta reduction bug
Merge pull request #2 from Gabriel439/debruijn

DeBruijn-like indices and substitution algorithm