Make opus_compare less tolerant?
multi-stream: check min size


draft:
- forward-reference redundancy CELT frames in section 2.
- List padding as extension mechanism?


JDR:
 - Improve Overview section
 - first two on p. 8
 - Define "packet", p. 9
 - padding data, p. 13 (extension mechanism?)
 - p.99

test vectors:
 - mono speech 1 min, 2-way sweep
 - mono speech 1 min, fuzz at random rate
 - mono music 1 min, 2-way sweep
 - mono music 1 min, fuzzing
 
