Add compileSampleStats

todo.txt

@@ -2,8 +2,8 @@
 - Throw if edit list detected
 - Add the new audio codecs to muxers
 - Mov muxer!!! Only mov can hold PCM audio, MP4 cannot
-- Metadata methods for computing average fps and bitrate
 - A stream source?? Or like a callback-driven source
 - onRead callback for Source
 - onHeader, etc callbacks for Matroska
-- Add cslg box
+- Add cslg box
+- https://github.com/Vanilagy/mp4-muxer/issues/83 tell him it's possible now