formatted source code according to the rust guidelines using rustfmt

[mathstuf]

Thanks. Is there a rationale document somewhere? The rustfmt repo seems to just point to a forest of "FIXME" notes from a cursory check.

Some things I have nits with:

• I like trailing commas after the last match subexpr, list item, etc. (though their utility is less when compressed like it is here, I prefer uniformity on that side);
• the vertical alignment in constants.rs and ffi.rs is preferred over the compression done here;
• I prefer local uniformity over line length limits[1] and the test blocks should either all be wrapped or none.

[1]In fact, IMO, strict line length limits tend to lead to worse style because how to break a line is not usually that well covered.

[jcreekmore]

So, rustfmt does accept a rustfmt.toml file in your top-level that lets you specify different options (sadly, this is the best reference I have found for the accepted options: https://github.com/rust-lang-nursery/rustfmt/blob/3ce2b840cf73253cedf86aaf3b6b7a71e27d6b79/src/config.rs#L259-L304)

[derekstraka]

It looks like I can create a toml file for 1 and 3. I'm not sure about the vertical alignment preservation though.