- added type class for looking up elements in scoped conversions

- number literals are parsed rather than stored as strings
- fix array query functions used on non-trivial number literals
- more efficient expression simplification recursion
- expanded constant folding scenarios

- significant refactor of struct conversion
- significant refactor of typedef conversion
- scoping support in multipack conversion
- scoping support in typeof conversion

- the ternary expressions were previously used to decide the direction
  of generated part selects
- this fixes an issue where ternaries were generated for LHSs

- struct conversion handles directionality of fields
- struct conversion supports minus part selects
- fixed incorrect handling of directional part selects in multi-packed
  conversion
- multi-packed conversion defines standard ranges in terms of
  directional part selects for clarity
- fixed potential loop due to overeager untagging in multi-packed
  conversion

- Trace comments cover module items, decls, and stmts
- Added pseudo-lexer to Alex parser for monadic Position production
- Added Position to every DeclToken
- Removed Comment PackageItem
- Added CommentStmt and CommentDecl
- Fixed traversal skipping outer MIAttr ModuleItems
- Generally cleaned up Parser modules

- dimensions flattening conversion only flattens packed dimensions
- conversion for packing arrays when necessary (preserves memories)
- added coverage for array with multiple packed dimensions
- test runner no longer forbids multi-dim accesses after conversion
- Decl and subordinate types derive Ord

This includes support for
- parsing dimensioned alias parameters
- flattening non-var decls with multiple packed dimensions
- converting arrays of structs
- inferring struct types for decls with initializations

- NestTF refactored to cover all package items
- fixed issue where type traverse skipped typedefs

- entirely new PackedArray conversion (always flattens)
- typedef and struct correctly order packed ranges when combining types
- Stmt LHS traversal no longer traverses nested statements to avoid double conversion
- Logic conversion applies to `initial` blocks`
- new and modified tests to cover these cases