shuffle.py v1.4

Full Changelog:

* Catch "no space left" error #30
* Renamed --voiceover to --track-voiceover
* Added optional --verbose output
* Renamed script from shuffle.py to ipod-shuffle-4g.py
* Added files to `extras` folder
* Ignore hidden filenames
* Do not force playlist voiceover with auto playlists
* Added shortcut parameters (-p, -t, -d, etc.)
* Fix UnicodeEncodeError for non-ascii playlist names (#35)