Refactor: fix clippy warnings

[mstallmo]

closes #477

This is a first pass PR at cleaning up the clippy warnings. Most of them were simple enough refactors that it only took minor modifications to the code to get rid of the warnings. There were a few warnings, marked by #![allow()], that would require more significant changes to the code structure so instead of going ahead and implementing those changes I marked them as clippy allow until we can decide if the changes are something we want or not.

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[ashleygwilliams]

this is great! sorry for the delay in reviewing. we should def make a second pass and see if we can't eliminate some of those allows. thank you so much!

[mstallmo]

Awesome! I should be able to fix up the conflicts this evening so everything will be ready to merge.

I'll also go ahead and file a new issue for working on removing the allows !

[ashleygwilliams]

@mstallmo i might be trying to get this into 0.6.0- would you mind if i took over and fixed the conflicts? i am just feeling guilty and don't want to delay the release any further <3

[ashleygwilliams]

actually, @mstallmo i'm gonna hold off and push this to 0.7.0- which should only be a month. go ahead and work on the conflict and we can get this merged in as one of the first PRs post release!

[mstallmo]

@ashleygwilliams Sorry for the delayed response but that sounds great!

[mstallmo]

Just pushed the update resolving the merge conflicts with master so this should be good to go as soon as the checks pass.

[ashleygwilliams]

i need to do #509 before this because it's more urgent- which may introduce another conflict- but i'll handle that for you! thanks so much for your work here!

[ashleygwilliams]

since we opted against a point release, we can get this into the next release (0.7.0) thanks!