AbiathRPC - Logging

I haven't had much time today to develop any of my fun projects, but I did slightly adjust AbiathRPC. It now logs the basic user actions: connection, disconnection, authentication attempts. Instead of using Console.WriteLine everywhere, there's now an actual logging method that includes the timestamp in the output. In the future, I'll probably have this also write to a log file.

(This "Anonymous" is the one with the publicly available VeriMaps certificate. AbiathRPC users need to provide a username to connect.)