very small speedup, not sure if it is worthwhile to do

- CT_LIT -> SHARED_THUNK
- CT_VAR only local vars, function names are converted to applications
- CT_APP dynamic/static. static case contains the correct descriptor pointer (to the slice)

+ "eval" where cannot be avoided

+ primitive functions set return value directly instead of returning it

+ execute a single VAR_FN when forced
+ refactor basic struct Desc definition to avoid cyclic includes

+ local vars
current running maximum:

:: _predefined._List = _predefined._Cons a1 a2 | _predefined._Nil

example.map f_0 !_x_1 = select _x_1 (_predefined._Nil -> _predefined._Nil) (_predefined._Cons a_1_0 as_1_1 -> _predefined._Cons (f_0 a_1_0) (example.map f_0 as_1_1))
example.inc !a_0 = add a_0 1
example.Start = example.map example.inc (_predefined._Cons 1 (_predefined._Cons 2 (_predefined._Cons 3 _predefined._Nil)))

+ ADT + Record
+ parameter passing