Committing the partial refactor of authentication services. No user functionlity

will eat your babies, etc

OpenSim/Services/Interfaces/IAuthenticationService.cs

@@ -32,10 +32,29 @@ namespace OpenSim.Services.Interfaces
 {
     public interface IAuthenticationService
     {
-        string GetNewKey(UUID userID, UUID authToken);
+        // Create a new user session. If one exists, it is cleared
+        //
+        UUID AllocateUserSession(UUID userID);
 
-        bool VerifyKey(UUID userID, string key);
-        
-        bool VerifySession(UUID userID, UUID sessionID);
+        // Get a user key from an authentication token. This must be
+        // done before the session allocated above is considered valid.
+        // Repeated calls to this method with the same auth token will
+        // create different keys and invalidate the previous ne.
+        //
+        string GetUserKey(UUID userID, string authToken);
+
+        // Verify that a user key is valid
+        //
+        bool VerifyUserKey(UUID userID, string key);
+
+        // Verify that a user session ID is valid. A session ID is
+        // considered valid when a user has successfully authenticated
+        // at least one time inside that session.
+        //
+        bool VerifyUserSession(UUID userID, UUID session);
+
+        // Remove a user session identifier and deauthenticate the user
+        //
+        void DestroyUserSession(UUID userID);
     }
 }