Add a rustfmt.toml file with some clean guidlines.

[brandonpollack23]

Note: Though seemingly large this change is a total no-op and run with cargo fmt only, just he simplest thing I could think of for a first issue.

This is based on my own rustfmt.toml I usually use. I tend to set these for the following reasons:

imports_granularity = "Crate" # this combines a bunch of lines at the top, but it doesnt match google style so I removed it tab_spaces = 2 # param lists and chained calls tend to be longer and more common in rust, I think this increases readability fn_params_layout = "Tall" # this is way easier to read than non tall format_strings = true
use_try_shorthand = true # replace any ugly try! macros with the pretty ? wrap_comments = true
max_width = 100 # If we can do it in Java, we can do it in Rust

for issue #74

[HidenoriKobayashi]

I'm mostly fine with this change, except for the tab_spaces.

Although, I can probably live with it, if everybody else prefers it to be 2.

[brandonpollack23]

Closing this PR because it is included in the "Starter Changes PR"

Feel free to comment on that for the PR to be split up at a certain point.