* set processing time
* merge labels and set on response
* use state cache for adding alerts to rules
* minor cleanup
* add support for NoData and Error results
* rename test
* bring in changes from other PRs tha have been merged
* pr feedback
* add integration test
* close state tracker cleanup on context.Done
* fixup test
* rename state tracker
* set EvaluationDuration on Result
* default labels set as constants
* separate cache and state from manager
* use RWMutex in cache
David Parrott
788bc2a793