Develop csc/vbc override tasks for Microsoft.Net.Compilers NuPkg so that NuGet users of Roslyn can use Analyzers at build time (VS2013, or non-Windows)

[theoy]

Currently, compiler users (even on VS2013) can easily upgrade to Roslyn by referencing the https://www.nuget.org/packages/Microsoft.Net.Compilers NuPkg. If they are staying on C#5/VB11, then they can even get a reasonably cooperative IDE experience.

However, if Microsoft.Net.Compilers included csc/vbc MSBuild tasks, they could also start using Roslyn analyzers as soon as they got the compiler NuGet.

This may be meaningful for customers who are not yet ready to upgrade to VS2015, or also for some NuGet users on Mono/non-Windows. Though we should check on the xbuild support.