Another attempt to deal with VS auto converting to .NET 4

git-svn-id: https://ironscheme.svn.codeplex.com/svn@109496 2327b42d-5241-43d6-9e2a-de5ac946f064
Check for other CLR 2 .NET versions too.

git-svn-id: https://ironscheme.svn.codeplex.com/svn@109498 2327b42d-5241-43d6-9e2a-de5ac946f064
Copyright  maintenance (OSS dead man switch?)

git-svn-id: https://ironscheme.svn.codeplex.com/svn@109516 2327b42d-5241-43d6-9e2a-de5ac946f064
Merge branch 'master' of github.com:leppie/IronScheme