/*
 * Calculate the crucial pieces of information for an MP3 file.
 *
 * Note: This method returns the duration of the MP3 in milliseconds, so
 * you'll need to divide the duration by 1000 before passing it to
 * MusicBrainz::TRM methods.
 *
 * Aliases:
 *   MusicBrainz::Client#get_mp3_info
 *
 * Examples:
 *   # get the duration and stereo of an MP3 named 'foo.mp3'
 *   info = mb.mp3_info 'foo.mp3'
 *   puts 'duration (ms): ' << info['duration'] << ', ' <<
 *        'stereo: ' << (info['stereo'] ? 'yes' : 'no')
 *   
 */
static VALUE mb_client_mp3_info(VALUE self, VALUE path) {