Java 7 and *Nix Compatibility

Changing several things to final to allow this to compile and run under Java 7.

Also, change hardcoded \\ (Windows only) to File.seperator which automatically sets \\ or / based on what the application is running on at runtime.

The changes in UserGUI are there because I was going to try to implement clickable links, then I realized it was harder than I thought. It would most likely require an EditorPane, and that would then require using an EditorKit.