Create .NET 4.0 branch?

Perhaps I'm missing something somewhere, but it looks that the GitHub version of PowerPack does not have the latest changes from CodePlex. I merged the changes here. 

Not sure what the best organization for GitHub repo is, but I'd suggest we should create a branch `net35` and probably have `net40` as the `master`?

(So do not merge this right now - just attaching the code for reference...)