mediascanner rejects valid media files without a file extension

[Jim Hodapp]

If I have any audio or video files in my collection that don't have a file extension (e.g. *.mp3), mediascanner refuses to add such a file to the scanned database. It should be able to do a deeper content type evaluation and still see that such a file might still have a completely valid mime type of audio/mpeg. Thumbnailer and now media-hub both support such files and mediascanner needs to support it as well so that they show up in apps like music-app.