Implement fakes for System.Web.*Provider to make all tests pass ...

.. with Sitecore 7. Without it some tests complain trying to go the default System.Web.Security.SqlMembershipProvider route. Also added a /Lib folder to put Sitecore references in (with a readme). You guys are referencing it via packages but I am not sure I can get Sitecore binaries as a NuGet outside of the core team room :) can I? Let me know what you think. I have been looking for a good test isolation framework for Sitecore and Sitecore.FakeDb is the most promising (and appears to be the most complete) of all. Would love to not only use it but also to contribute.