add a new SimpleMovingAverage class, replaces CounterStats
add SimpleMovingAverage to each Agent, collect bytes received stats
put back brad's voxel stats, he loves them too much
Merge remote-tracking branch 'upstream/master' into mixer-stats
rename the _movingAverage variable so it is more descriptive
add a decay to the event delta average
Merge pull request #87 from birarda/mixer-stats

stats refactoring via change to SimpleMovingAverage