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

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

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

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

This finally fixes the issue where trying to list a file causes a crash. Also, tidy up some of the uses of references.

Also, rename old 'lines' view to 'details' which makes more sense

- Lifetime changes in unix.rs
- lexical_ordering -> cmp
- from_utf8_lossy got moved into String
- vec.get(n) -> vec[n]

This makes it more like ls. The --long (-l) argument has been added to get at the old behaviour, and the --links argument is now on -H. I can't crib this behaviour from ls because it shows it by default.

TODO: The terminal size is currently assumed to be 80, and it uses the string length, rather than the width.

First non-trivial change for a while... because this involves reading from the OS, we should cache as much as we can in memory. So, group membership checking is done immediately after reading a group name, as the group structure has already been populated.

This is behaviour cribbed from ls. Even though I've never personally used it, I'm sure someone has a use for it.

- s/syntax/phase
- no more boxed array syntax
- getopts fail implements Show
- option#expect now requires &str