Mad they said! It could not be done they said! I proved them wrong!

Changelog:
 1. Generic LinkedList:
  - By the power invested in me by the Holy Sanctity: the POINTER, generic
    lists are now possible.
  - It's so generical that every Node can have a different value type.
  - This can be overriden of course by type checking before adding.
 2. intern_func is now _list_func.
 3. print(...); = printf(...); + \n