- fix wildcard imports shadowing other items
- fix explicit imports depending on other items
- fix example export in package.sv

- handle cases where wildcard equality short-circuits to 0
- move checking for extraneous X/Z to wildcard conversion
- add exhaustive test coverage

- removed repetition in dimension query conversion
- removed repetition in package item nesting conversion
- packing item nesting conversion short circuit
- param type conversion doesn't bother renaming non-param type instances
- implement showsPrec for certain expression cases

- most binary operators
- ternary expressions
- bitwise negation
- number literals
- size casts
- concat and repeat expressions

- single bit localparams retain explicit range
- fix $bits on unsized literals
- use Implicit over Maybe for underlying type

- fix position modport-to-modport bindings
- inout logics converted to regs become outputs

Some .v files are incorrectly identified by GitHub Linguist as Coq or Vlang
files, which confuses people who browse the repo on GitHub. According to
https://github.com/github/linguist#using-gitattributes adding a .gitattributes
file can solve this problem.