Code cleanup to improve readability

[Rigidity]

This PR aims to resolve a few issues within the code:

• All cargo clippy warnings have been resolved
• A lot of variable names are a single letter in length, when they should be a little bit more descriptive.
• Doc comments not directly attached to the function which they describe.
• Comments not being capitalized and punctuated properly.
• Code too tightly grouped together, hard to mentally process all at once.
• According to the Test Organization page on the Rust book, tests should be grouped together within a tests module.

Non-code changes made:

• Update .gitignore to include both target folders as well as Cargo.lock.
• Remove Cargo.lock from the repository.

This PR does not do any of the following:

• Change the functionality of any of the code.
• Break the public API.
• Break anything when running the cargo test command.
• Document anything that wasn't already documented.
• Change the code in any of the Python bindings.

[coveralls-official[bot]]

Pull Request Test Coverage Report for Build 5439039662

• 1323 of 1340 (98.73%) changed or added relevant lines in 16 files are covered.
• 4 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.07%) to 93.88%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/serde/parse_atom.rs	126	127	99.21%
src/serde/tools.rs	158	159	99.37%
src/allocator.rs	300	307	97.72%
src/serde/object_cache.rs	132	140	94.29%
<!--	Total:	1323	1340	98.73%	-->

Files with Coverage Reduction	New Missed Lines	%
src/allocator.rs	1	95.79%
src/serde/read_cache_lookup.rs	1	98.15%
src/serde/parse_atom.rs	2	98.24%
<!--	Total:	4		-->

Totals
Change from base Build 5332718148:	0.07%
Covered Lines:	5246
Relevant Lines:	5588

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💛 - Coveralls