Added ListItem.Votes and VideoPlayer.Votes

This commits adds ListItem.Votes as well as VideoPlayer.Votes to display a label only containing the string "%s Votes" for IMDB rating.
The combined label RatingandVotes (returning "RATING (%s votes) " ) doesn´t work too well for more custom layouts (for example multilined).
Alternative to "%s votes" would be to only return the integer so the skinners could choose themselves how to display it.