* Correctly group labeled matrics in rendered output. (HT: @kbucheli)
* Fix a problem with thread-safety when using labeled metrics. (HT:
* Improved performance of metrics rendering. (HT: @kbucheli)
* Fix namespaces, units, and other name related terms that were being used
incorrectly in samples.
* Fix the internal metric factory to make sure it builds metric groups
* Fix the labels method of metric groups, which was completely broken.
* Initial revision.