Worked on vector-related performance

[Kixiron]

• Pre-allocated vectors wherever possible in order to reduce the total amount of allocations preformed

[jyn514]

Most of these would be better written as maps IMO.

[Kixiron]

Changed the vast majority to maps, some really didn't lend to it

[jyn514]

Lots of comments! Most of them are just nit-picky things, I'm happy to have them addressed in a follow-up PR instead.

[jyn514]

Thanks so much for working on this! Little things like this are easy to forget about but they make a big difference :)

[jyn514]

I would like to add tests for these before merging. See e.g. https://github.com/rust-lang/docs.rs/blob/master/src/web/mod.rs#L617 for examples of how to write tests, and you can visit the pages on docs.rs to see what the expected behavior should be. I know there's a lot of changes, it might be easier to add tests in a separate PR and merge that first.

[Kixiron]

Git hates me and closed on its own

[jyn514]

Status: this needs to be rebased and needs tests to be written.

[jyn514]

I was a little picky on the last review. This looks good once you rebase and address the outstanding comments (I resolved a lot of them). db/file.rs changed a lot in #643 so you might want to make those changes in a follow-up PR instead of trying to rebase.

[Kixiron]

@jyn514 Fixed

[jyn514]

Thanks for all the hard work! Unfortunately I took long enough to review that there are merge conflicts. Once those are resolved (preferably through rebasing, not merging) this looks great.

[jyn514]

🎉 🎉