- event expressions use Expr over LHS
- stricter AST representation of event controls
- property specs use event expressions directly

Specifically, support has been added for non-ANSI style port
declarations where the port declaration is separate from the
corresponding net or variable declaration.

- moved 4 phases to initial set and 3 to final set
- fix synthetic unnamed genblocks preventing name resolution
- asgnop conversion folds in unisub when possible

- convert loops with no or many incrementations
- restrict AST node to only contain traditional initializations
- parser elaborates for loop decls into a synthetic block
- decl list codegen is now specific to parameter decl lists
- update jump conversion special cases for new representation
- first experiments with bimapM

- avoid premature conversion of default struct type parameters
- allow use of $clog2, $signed, and $unsigned in type parameters
- more thorough and efficient top reference ident renaming
- precede type param conversion with hier const pass

- delegate cast type and sign resolution to TypeOf conversion
- internal support for injecting data declarations into statements
- fix size and sign of unbased unsized literals used in casts
- avoid generating many unnecessary explicit casts
- support casts which depend on localparams within procedures
- expression traversal correctly visits types within type casts
- fix typeof on expressions of net types
- handle additional edge cases for unsized integer array patterns
- preserve signedness of implicitly flattened unpacked integer arrays

- ensure concats and repeats stay unsigned
- defer unbased-unsized conversion to enable cast semantics
- disable inaccurate folding of binary operations of based numbers
- fix typeof and size cast binop signedness logic
- fix typeof $unsigned and $signed
- test harness allows production of `integer unsigned`

- full import and export support
- simplify AST representation of import and export
- allow package-scoped identifiers invoked as subroutines
- use scoped name resolution for identifiers in packages
- merge package item nesting conversion into package conversion
- fix handling of colliding enum items in separate modules
- fix visiting enum item exprs in types

Yosys does support some asserts nowadays. Allowing sv2v to not strip
them out means that you can check formal properties without needing
hierarchical references (which Yosys really doesn't cope well with!)

- 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