- now properly records the scopes
- only register requested ones

Contract resolution still need to be done as well as dealing with the machine code level and so on.

- arrow.ml* to define basic builder for arrow (node, name, ...)
- machine_code_common similar to corelang but for machine_code (printers, some builders, ...)
- machine_code restricted to the translatation from normalized nodes to machines

Structs defining machines are now in machine_code_types