- uint -> usize
- getopts Cargo library
- replace feature gates with unstable APIs

Also, remove dependency on the Regex library by replacing the one place it was used with standard code that should hopefully be faster anyway.

std::str changes, and the way macros are expanded.

Now the grids are optimised so each column is only as wide as its longest file name. The method could do with some optimising, but at least it works.

Different types of user caches could come in the future...

- Prefer iter over into_iter where appropriate
- Cut down on cloning

I'm serious, the more functionality I can use external crates for, the better.

Feels good turning all that code into a dependency!

I can't complain, because the breaking changes were caused by my pull request...

With suggestions from helpful #rust folk. Thank you!

Yeah, I broke my own code again.

Also, re-use the stat result from directory-checking.