Rust API Guidelines compliance

[veeenu]

We should refactor the whole library to adhere to the API Guidelines. This checklist should guide the work.

[thompsondt]

Are you tracking this somewhere? I'm just getting into Rust and this may be a great opportunity for me to practice the language and pitch in on a good project.

[veeenu]

Absolutely, that's much appreciated!

Not really tracking this effort much honestly, due to the fact that the time it takes finding non-complying areas dominates the time it takes fixing them -- it's mostly very small refactorings/renames and stuff can and will slip through in the future anyway so it's faster to just change stuff as one finds it.