Create an eta-expander module

[fredins]

This program type checks but wont work for the latter parts of the compiler

add : Int -> Int -> Int
add x y = x + y

apply : forall a. (a -> a) -> a -> a
apply f x = f x

plus4 : Int
plus4 = apply (add 4) 2

A new module needs to be created that expands (add 4) to (\x. add 4 x).
This module is after the type checker and before the lambda lifter.