Review outdated content mentioning old versions of VS

[mairaw]

There are a lot of topics that still mention old versions of Visual Studio.

For example, see this query for Visual Studio 2010:
https://github.com/dotnet/docs/search?utf8=%E2%9C%93&q=visual+studio+2010&type=

When we can, we should avoid talking about a specific version unless we're saying when a feature was introduced or showing version history.

Also note that topics can be using the token file (for example, vs_dev10_long_md.md) instead of having the text in the topic itself.

We'll be redirecting the latest version of C# and VB topics from MSDN to docs soon, so topics can be applicable to VS 2015 and 2017.