Christiaan Hofman

no need to reload file view when updating previews, they will be reloaded separately through updateFileViews when needed

initially display correct preview display, except for teX which needs to be set up properly

move headers to headers group

Use split view controllers for editor

use correct splitview to set fraction

declare IBOutlet for delegate and dataSource

Replace splitviews in document window y splitview controllers. Add nibs and view controllers for component views in document window.

remove unused method implementation