More work on the screen system

Set up an example to show how you can easily change between the screens
using the framework I have put together.
Implemented the start of a logging system

The logger class currently displays debug messages but eventually I will
implement a filter system that will let me specify what type of message
to display. The message types will be Debug, Error and Server. The
Server message type will be for when the user is hosting a server and
showing the window.