Modernizing codebase

[jamiepollock]

In this PR I've modernized some of the aspects of the codebase. E.g. file-scoped namespaces as well as adding a blank EOL.

The latter is unrelated, more of a styling choice.

I've stopped short of adding nullability. That's a larger change which could be tackled in a separate PR.

[Nicholas-Westby]

I haven't reviewed this in detail, but feel free to merge it whenever. I don't understand what you mean by "adding a blank EOL", but I'm sure it's fine whatever it is.

[jamiepollock]

@Nicholas-Westby that’s a git convention. I think I meant EOF end of file… leaving an empty EOF line. Most clients like Sourcetree flag this as missing.

[Nicholas-Westby]

@jamiepollock If you are referring to the blank line at the end of a file, I think that used to be a thing with C/C++, but never really C# for weird compiler reasons. Doubt it's relevant today. If it's instead some invisible "end of file" character that isn't just a blank line, that may be fine. I wouldn't recommend applying this to a bunch of repos without further discussion though (e.g., to talk about usefulness).

[jamiepollock]

@Nicholas-Westby I agree. I think we should discuss this on Monday. I'll look at ways of removing this behavior from Sourcetree if possible. We should have a consensus at least.

I may amend the PR and rollback that change.