message: fixed timing error in Meter
  was always passing in NaN
diff: @@ -3,12 +3,11 @@ define(["helper/Offline"], function (Offline) {
  return function(callback, duration, channels){
  return Offline(callback, duration, channels).then(function(buffer){
  - var blockTime = 512/buffer.sampleRate;
  var rms = buffer.getRMS(512);
  rms.forEach = function(callback){
  for (var i = 0; i < rms.length; i++){
  var level = rms[i];
  - callback(level, blockTime * i);
  + callback(level, i * buffer.sampleTime);
  }
  };
  return rms;
  