for functions:

During initial loop scanning:
- Check arguments:
    - If "site dep." arguments, flag them
    - If "out"-parameters or non-const. method mark possible site dependency chain 
        - NOTE: may change site dependence of expression, is_site_dependent()
- Tally up function pointers, and site dep. of arguments on a loop_func vector

Post-process:
- site dep. of loop variables -> Function arg site dep.
- Revisit function:
  - check site dep. of local variables -> dep. chain. 
  - check called function arguments -> site dep.
  - check local var dep -> function arg site dep.
     -> go in called functions
  - If all functions which should be are vectorizable, and local vars vectorizable -> vectorizable
        - note: only if local var is template can be upgraded (functions are not rewritten(?))




NEW - miniman solution:

