Fixes ticket:416, "oggz-chop writes wrong granulerate in fisbone"
by correcting the library behaviour.
  - Rename internal oggz_auto_get_granulerate() to oggz_auto_read_bos_packet()
  - Add internal oggz_auto_read_bos_page()
  - Use oggz_auto_read_bos_page() when a new bos page is encountered, before
    calling the user's page reader callback
  - Correct the granulerate denominator reported by oggz_get_granulerate,
    removing the internal OGGZ_AUTO_MULT scaling


git-svn-id: http://svn.annodex.net/liboggz/trunk@3718 8158c8cd-e7e1-0310-9fa4-c5954c97daef