Add StyleCop.MSBuild

[adamralph]

https://nuget.org/packages/StyleCop.MSBuild/

We can also add

<StyleCopTreatErrorsAsWarnings>false</StyleCopTreatErrorsAsWarnings>

in the csproj files if we want to enforce compliance.

[philippdolder]

I agree. Using StyleCop in all my customer's projects. But we need to tweak the settings a bit. I don't want comments to be enforced for example.

[adamralph]

My usual preference for an API is to enforce documentation for public members but not for internals and privates but I'm happy to go with the consensus. If there are a lot of public members currently missing documentation then this is not practical in the short term anyway.