Move 'create_metrics' to be rest of metrics code.
Add an explict command line check of seconds before failover.
Add comment about heartbeating channel.
Post merge fixes.
Cleanup code.

Remove obsolete codes and some obsolete TODOs.
Some performance improvements for comparing two vectors.
Add Easylogging++ as logging library for barn-agent.

As barn-agent logs get mixed together it can be hard to distinguish one
agent from another. Need to prefix log messages with the service_name that
the agent is reporting.
It appears Easylogging++ (http://easylogging.org/) is the simplest logging
library to solve this.

Also moved barn_conf to params.h where it seems more natural and stops the
circular dependence of barn-agent.h with other header files.