Various fixes for the generators and helper functions.

- Check structure types recursively for sized types
- Modify annotate function to pop stack.
- Add annotations for debugging to a lot of generators.
- Fix a bug in normalize_type_GenLLVM where pointer types were not
   normalized fully.
- Add a note about #361
  + Originally had fixed the is_sized_type_alias parameter, but this
      caused problems in other generators.
- Make normalized_typ_eq compare identifiers for types. This should
   probably be improved further (rename the function + make this
   follow identified type definitions when they're not
   structures. Related to the #361 issue).
- Avoid using normalized types in a few generators.
- Add gen_exp_possibly_non_deterministic to generate calls (as we now
   mark global pointers as non-deterministic).
- Fixed bug in gen_new_definition where function types would be
   generated inside vector types.