- obey exif orientation tag

According to http://www.daveperrett.com/articles/2012/07/28/exif-orientation-handling-is-a-ghetto/ PreviewImageFragment obeys the EXIF orientation tag.
Please add comment, e.g.:
/**
 *  Rotate bitmap according to EXIF orientation. Cf. http://www.daveperrett.com/articles/2012/07/28/exif-orientation-handling-is-a-ghetto/
 *
 * @param bitmap Bitmap to be rotated
 * @param storagePath Path to file containing EXIF information. Should be path to bitmap, of course.
 * @return correctly EXIF-rotated bitmap
 */