Add "newtype" functionality

[stylewarning]

Add "newtype" functionality

[eliaslfox]

Semi optimal codegen won't be that trivial.

Calls to wrap and unwrap a newtype should be elided from the ast. Except that calls to wrapping and unwrapping can be captured as a parameter.

Also we probably want a peephole optimizer to look for calls like this

(define xs (map unNewtype ys))

And rewrite them as the following

(define xs ys)

[stylewarning]

Wrapping would just be the identity function, which can be declared inline.

Unwrapping would be special codegen on MATCH, since there's no way to unwrap otherwise.

Eliding use of high-order functions is a bit harder, but the above would be a great first step.