- connections are now matched to format plugins based on content-type headers,
   and are rejected if there isn't a format handler for that content-type, or
   there is no content-type at all.
 - format_vorbis now handles pages with granulepos of -1 in the headers
   correctly (this happens if the headers are fairly large, because of
   many comments, for example).
 - various #include fixes.
 - buffer overflow in httpp.c fixed.

svn path=/trunk/avl/; revision=3042