Add NuoDB .NET Membership Provider

This contains the first implementation of a  .NET Membership Provider for NuoDB.  It is built as a separate .NET Assembly NuoDb.Web.Security.  I have manually tested this with a separate ASP.NET application.  If this looks ok, then we can add that sample application or modify the existing ASP.NET sample application to use this membership provider.  The changes that are needed for the installer have not, yet, been done.