Viewer crashes if any trophy collection packages have been removed

If a user removes a trophy collection package (for example ubuntu-desktop-accomplishments) and does not restart the Accomplishments Daemon, the viewer will crash due to missing trophy images:

Traceback (most recent call last):
  File "/usr/bin/accomplishments-viewer", line 47, in <module>
    accomplishments_viewer.main()
  File "/usr/lib/python2.7/dist-packages/accomplishments_viewer/__init__.py",
line 51, in main
    window = AccomplishmentsViewerWindow.AccomplishmentsViewerWindow()
  File "/usr/lib/python2.7/dist-packages/accomplishments_viewer_lib/Window.py",
line 48, in __new__
    new_object.finish_initializing(builder)
  File "/usr/lib/python2.7/dist-packages/accomplishments_viewer/AccomplishmentsViewerWindow.py",
line 237, in finish_initializing
    self.finalise_daemon_connection()
  File "/usr/lib/python2.7/dist-packages/accomplishments_viewer/AccomplishmentsViewerWindow.py",
line 500, in finalise_daemon_connection
    self.update_views(None)
  File "/usr/lib/python2.7/dist-packages/accomplishments_viewer/AccomplishmentsViewerWindow.py",
line 828, in update_views
    icon = GdkPixbuf.Pixbuf.new_from_file_at_size(str(acc["iconpath"]), 90, 90)
  File "/usr/lib/python2.7/dist-packages/gi/types.py", line 76, in constructor
    return info.invoke(cls, *args, **kwargs)
gi._glib.GError: Failed to open file

Some fault tolerance should be added for example to restart the daemon process to update configuration instead of letting the viewer crash. A daemon restart fixes the problem but end users cannot be responsible of knowing to do this.