Changes to File and Image Upload Forms

The File and Image upload dialogs now ask for information about the origin of the file and how it can be reused. This information is in turn made available to visitors who might want to use the file in their own work. The upload forms now also tries to automatically discern the type of file. This should eliminate some confusion resulting from people choosing the incorrect file type when uploading files. It's still possible to over-ride these 'guesses' if you need to specify a particular file type; especially one that's not recognized by the system.