- general refactoring throughout
- improved metrics for dropping unneeded modules
- fix re-visiting a converted instance in the same pass

- fix type/expr ambiguity for interface and class parameters
- check for parameter kind mismatch up front
- centralize key logic in ResolveBindings

- variable-size string parameter conversion restricted to modules which
  depend on the size of the string parameter
- string localparams are typed as appropriately sized vectors
- remove ordered parameter binding logic from string param conversion

- `expr.name[idx]` considers `expr.name` could be a struct array
- remove fallback struct type lookups which were guaranteed to fail

- preproc reads identifiers unconditionally
- drop leading whitespace for default macro args
- very minor preproc cleanup