- pattern keys now represented as TypeOrExpr
- support for simple integer struct pattern keys

- previously the overrides for parameterized data types could only
  reference data declarations at the module scope
- their use within procedures is still allowed, but cannot currently
  refer to localparams declared within procedures
- add procedure scope location accessors to allow scoped traversals to
  mark where injected items will end up in advance

- disallow using end label alone on blocks
- improved parse error for mismatches
- add label checking for non-block constructs
- allow generate block to have label before begin

- 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