Merge pull request #2 from Alexey-Yakovenko/master

Merge branch
Fix for issue #1116 (work round Vorbis issue #1486)
Fix for issue #1116 (work round Vorbis issue #1486) - typo
Only change seek offset for multiplexed files with Vorbis not the 1st stream
Merge pull request #12 from Lithopsian/libvorbisfile

workaround for libvorbisfile bug, causing hang after seek to sample 0 in multiplexed streams (bug #1116)