control/media_instance.c: Fix a segfault caused by libvlc_media_instance_release. (Patch by Enrique Osuna).

  Someone should check if we could make xtag not send ENDELEM for self-closing tags, as libxml doesn't.

(libmpeg2/xvmc pending)

decoder block_t date to a display date (identify for now)

 - Remove configurable boundary that had never been working anyway (did not match the original value from MUX_GET_MIME)

the only demuxer supported is mpga, other demuxers should be updated if they demux files that can have id3v2 tags
fix some bugs in flac & ogg demuxers

input_ExtractAttachmentAndCacheArt(): use the attachment's mime type, don't use input_item_ functions as the input_item_t has been locked previously.