added fetchMetadata() in youtube player
prevent loader.loadJSON() from crashing when returned data is not JSON
fetchMetadata() now uses loader.loadJSON()
added fetchMetadata() in soundcloud player
added fetchMetadata() in vimeo player
added fetchMetadata() to dailymotion player
added fetchMetadata() in deeper player
added (incomplete) fetchMetadata() in bandcamp
added fetchMetadata() in jamendo player