Description
   Gtk_FileDrop provides an easy interface to
   set up GtkWidgets to receive files via Drag'n'Drop. Widgets can be
   told to accept a number of MIME-Types as well as a number of file
   extensions. Values of widgets can automatically be set when drops
   with valid files occur, or a callback function can be specified
   which is invoked in this case.
  
   Now one may think that the whole setup process is really simple
   and would not need a class like this to make widgets accept files.
   That is right. The setup for making widgets accept drops is an ease
   - but there are two more steps to do:
   
Make the widget accept only some types of 
    files
Convert the dropped filenames to usable 
    filenames
  
   The first item is not so hard to implement; we do this by either
   checking the file extension, or using the MIME_Type package to
   get the mime type. (Note: * is supported).
  
   The second item is the main problem as all applications seem to
   ignore the standard for file name exchange and cook their own
   soup (so using their own format) when passing the file names.
   This package knows the differences and converts the dropped
   strings into usable local filenames, regardless of the format
   the source application uses. For a deeper insight in this topic
   you should read the PHP-Gtk FileDrop tutorial.
  
Note: A note about Mozilla/Firefox: Mozilla provides file names
   only with mime type text/plain only instead of 
   text/uri-list. If we would accept this type
   as well, the problem arises that every text could be dropped -
   if it is a file or not. That's why the decision was made not
   to accept drops from Mozilla.