Formatting fixes to rustfmt 1.5.1-stable

[johnoneil]

This PR just applies format changes from running cargo fmt on latest Rust stable. The version of rustfmt used is therefore 1.5.1-stable.

I'm about to use this crate to do a Proof-of-Concept for another thing needed at work, so having these formatting corrections in place will be helpful.

If there's any undesirable formating changes the PR could be updated with the correct macros to disable the pass over certain files/structs/functions.