* Fixed a bug in the performance counter query when run against SQL Server 2016 SP1-CU2. The performance counter DMV contains duplicate entries which are not handled by the query.

* Adding more stats related to workload groups.

* Adding new RG stats, removing "host" tag

* Removed workload group query

* Fixing some 2008 compat issues, removed the host field from the result set.

* Adding fixes for SQL Server 2008 compat around RG columns. Also converted perf counter query to support named instances.

If the command failed with a non-zero exit status there might be an error
message on stderr. Append the first line to the error message to ease the
search for its cause.

May be aggrevating timeout issue on appveyor builds.

This plugin can perform the standard metric modifications using override semantics.