Update code style with clang-format

[bghgary]

Some notes:

• I only did this for the Library folder. I don't think we need to do it for the other files. Ideally, we should only do it for Library/Include and Library/Source.
• Use style based on LLVM.
• @syntheticmagus and I decided that {} initializers should not have spaces inside to match LLVM defaults.

There are some weird bugs with clang-format. I either used // clang-format off, rearranged the code, or just didn't bother. Here are some notable ones:

• { style for initializers. They should be on their own line, but I couldn't find a way to work around it.
• Continuations with .then is really wonky if there are multiple continuations. The style AlignAfterOpenBracket doesn't seem to work for multiple continuations.

[CedricGuillemet]

I'd keep the clangformat style file in the root.
Otherwise, everything is fine.

[bghgary]

I'd keep the clangformat style file in the root.

I don't have a strong preference, but the way .clang-format works right now is kind of bad if you have submodules that don't have .clang-format. Maybe I can add a .clang-format to Dependencies to prevent it from leaking into submodules and move the repo one to the root.