[CSI] visual studio downgrade recommendation

[Mikhail Nesterenko]

CSI, CS3 students,

For home installation instructions on CSI lab website, we used to
recommend installing Visual Studio Community 2017. However, there are
several issues with this release: it may have trouble configuring a
project without pre-compiled headers, keeping the console opened after
project finishes (even with ctrl+f5 is pressed), issues running the
debugger.

So, we now advise to get the earlier version of 2015. 

I updated the link on the "Home Installation Instructions" page. So,
if you have installed the Visual Studio 2017 and have no problems, you
are welcome to keep it. If you have not installed it yet, or are having
issues with 2017, you are advised to go with 2015.

Thanks,
-- 
Mikhail