Add unit tests

[DBecker7]

Some things to test:

• [x] parse_mutations works as expected.
• [x] Ensure the results of provoc are inside the simplex.
• [x] Ensure lineage definition matrices are reasonable.
• [x] Ensure estimate is within the bootstrap confidence interval.
• [ ] ...

[JeremyFaria]

I will add unit tests for each of the requested items to test (it appears parse mutations already has one created). I will use the usethis package to automatically create unit tests for each file by going in the console and going use_test() with the the required files opened. I will then create appropiate unit tests by testing for every casenerio to ensure that the results are resonable/work as expected (depending on the item I am testing). I will update what I am doing for each test as some of the items require vastly different unit tests