Contribs: update vorbis to 1.3.4

"The primary feature of this release is reduced static data size in
 libvorbisenc."
"No functional changes, but the encoder lib is now a shade over 25% the
 size it was in the 1.3.3 release."

Before: libvorbis_plugin.dll: 1.7MB
After:  libvorbis_plugin.dll: 717kB