Castle core dll update

The Castle.Core was upgraded to v2.5.2, and the Castle.DynamicProxy2.dll was deleted.
Due to this, some namespaces were updated.

Also, an issue arose when trying to mock a delegate because of the proxy created by the new castle core code. The MockDelegate method was fixed to support the new proxy.

Oh, and also the Rhino.Mocks.sln was changed to VS2010.