Mahcade Crashes due to Fuzzy artwork.

[Zombie Ryushu]

This happens with revision 134.

Traceback (most recent call last):
  File "/usr/share/games/wahcade/joystick.py", line 201, in poll
    event_cb(active_window, e, "JOYSTICK", mw_key)
  File "/usr/share/games/wahcade/win_main.py", line 619, in on_winMain_key_press
    self.sclGames.update()
  File "/usr/share/games/wahcade/scrolled_list.py", line 97, in update
    self.signals['update'](self._ls_idx)
  File "/usr/share/games/wahcade/win_main.py", line 922, in on_sclGames_changed
    (i + 1))
  File "/usr/share/games/wahcade/wc_common.py", line 201, in get_artwork_image
    IMAGE_FILETYPES)
  File "/usr/share/games/wahcade/wc_common.py", line 148, in get_matching_filename
    f = re.search(p,fn)
  File "/usr/lib64/python2.7/re.py", line 142, in search
    return _compile(pattern, flags).search(string)
  File "/usr/lib64/python2.7/re.py", line 242, in _compile
    raise error, v # invalid expression
error: bad character range