Bolds the title text; bumps up the margin by a pixel to account for the engrossing window border.
Adds some more sketches of what the screens will look like (rough).
Adds viewmodels for various views of the application.
Adds ContentTemplateSelector which will choose the correct template to display the data depending on the item passed in. For now, this uses the "Name" property which is not as robust or extensible as it could be. Ideally, this ContentTemplateSelector would choose based off of type (which could be accomplished by creating a custom class based off of TreeViewItem).

Updates the .csproj with the new files added.
Creates some DataTemplates as an application-wide resource.
Updates MainWindow to create the DataContext XAML-side.
Adds some window-level resources, including the ContentTemplateSelector (important) for the content pane.
Adds a TreeView side panel and the content panel, which chooses its view based off of the TreeView's selected item.