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

- fix preservation of loop variables when breaking
- extend Yosys-compatible constant loop conversion to support loop
  variables declared outside of the looop

- 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

- renaming applies to nodes within generate blocks
- renaming applies to LHSs

- remove -o/--oneunit, has been the default behavior
- revise test coverage for default vs. siloed behavior
- add test to ensure README usage matches CLI help text
- remove -V alias for --version
- remove -? alias for --help