Cleared out the Resources folder so it could be used (properly) for XAML resources.

Added pretty buttons to all windows.
Updated namespace. Will need to move this enum later.
Added lesson name field to view model.
Revised all XAML windows (except the MainWindow) to have much, much, much nicer XAML layouts rather than awful absolute positioning Grid-based layouts.
Updated root namespace and application build name.

Removed unnecessary using directives.