Updated Workflow Developer Center

We've updated our Workflow Developer Center on MSDN.  We've simplified the design and refreshed the site with updated links.  As part of this work, we've also pulled together a list of key WF samples.

Our goal is for this to be a go-to site that aggregates key Workflow resources, including documentation, samples, videos, and other important links.  

Let us know what other content you think is important and what else you'd like to see on the site.