Add packets-per-second stats; fix muting bug

The logging for muting was broken.
Initial implementation
Reiterated according to suggestion from André.
forgot semicolon as usual....
fixed according to comments
add util.js
Adding trace events with id and start converging into a chrome devtools report structure.
rewrote average as a for loop
Fix js style.
Merge pull request #280 from GoogleChrome/moarstats

Add packets-per-second stats; fix muting bug
Changes in messages and report an event with the values.
Merge pull request #301 from GoogleChrome/encodeUsageTime

Check encode time for mandatory resolutions.
Addressed review.
Merge pull request #314 from GoogleChrome/testrtc-report

Adding trace events with id and start converging a JSON format.
Added AppRTC parameters
Merge branch 'master' of https://github.com/GoogleChrome/webrtc

Merge
Added changes following uberti/jiayliu review