HIGH
====
* give an option to ignore/bypass any non-readable files.
  Dialog with file names, buttons to backup anyway, always backup anyway,
  cancel backup

Medium
------
* proper check of existing rdiff-backup-data directory upon overwrite

low
^^^
* I hit a weird bug trying to backup to a FAT formatted USB key, but
  then I reproduced the same problem using rdiff-backup by hand, so that's
  probably not a huge concern for you.  I need to get a newer rdiff-backup
  (1.0 is apparently now out) and see if that fixes things.
* move each set into the treeview's liststore rather than keeping them
  as a list in rdiff_interface
