Add BaseOutputPath to common targets
Add BaseOutputPath to common targets

While this is not officially supported on non-sdk projects,
 NuGet Pack targets need a common output path
 to put '.nupkg' across both type of projects

AndyGerlicher/msbuild,mono/msbuild,rainersigwald/msbuild,AndyGerlicher/msbuild,mono/msbuild,rainersigwald/msbuild,sean-gilliam/msbuild,AndyGerlicher/msbuild,rainersigwald/msbuild,sean-gilliam/msbuild,mono/msbuild,sean-gilliam/msbuild,mono/msbuild,AndyGerlicher/msbuild,rainersigwald/msbuild,sean-gilliam/msbuild