Dont barf when there are no formats available.

src/libprs500/gui2/dialogs/lrf_single.py

@@ -65,7 +65,8 @@ class LRFSingleDialog(QDialog, Ui_LRFSingleDialog):
         self.changed = False
         self.read_saved_options()
         self.initialize_metadata()
-        formats = [i.upper() for i in self.db.formats(self.row).split(',')]
+        formats = self.db.formats(self.row)
+        formats = [i.upper() for i in formats.split(',')] if formats else []
         try:
             formats.remove(self.output_format)
         except ValueError:

src/libprs500/library/database.py

@@ -12,7 +12,6 @@
 ##    You should have received a copy of the GNU General Public License along
 ##    with this program; if not, write to the Free Software Foundation, Inc.,
 ##    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
-from libprs500 import __appname__
 '''
 Backend that implements storage of ebooks in an sqlite database.
 '''