Added another argument to strings::format.

Review: https://reviews.apache.org/r/16855
Removed the deprecated monitoring statistics.

Review: https://reviews.apache.org/r/12765
Reverted metering from Statistics.

Review: https://reviews.apache.org/r/12766
Added a List type in stout.

Review: https://reviews.apache.org/r/17029
Exposed TimeSeries and added "sparsification" of older values.

Review: https://reviews.apache.org/r/13603
Refactored the ResourceMonitor to use TimeSeries directly instead of Statistics.

Review: https://reviews.apache.org/r/13604
Updated the monitoring endpoint to return instantaneous values.

Review: https://reviews.apache.org/r/13605
Added a Top abstraction to the webui.

This allows the webui to asynchronously update resource consumption
information without every Slave controller having to implement this.

Review: https://reviews.apache.org/r/13606