use Tremor decoder instead of libvorbis.
drastically speed up Tremor by avoiding integer multiplications with more than 32 bits (lower precision)
Merge branch 'master' into tremor

Conflicts:
	compileOgv.sh
Merge branch 'master' into tremor
Update 'tremor' (integer vorbis library) branch

Not sure there's a clear performance advantage, but it saves us about
200kb off the produced JS to use this instead of libvorbis straight.
And it's easy to switch back if we choose.
Update readme for tremor