Deprecating old group communication

removing the premature commit of next gen group communication.
Removing @author tags from reef-io
Merge pull request #952 from Microsoft-CISL/shravan_nggroup_del

Deprecating old group communication
Merge remote-tracking branch 'origin' into reef-bridge
wait for CLRBridge to be ready before invoking failedEvaluatorHandler
update failedEvaluatorHandler for driver restart case, and block asking for another evaluator in restarted driver
add EvaluatorsChangeLog to HDFS, trigger failedEval when eval failed during driver restart, remove dependency on local file
Merge branch 'yingdac-evaluators-checking-back-in' into reef-bridge
close hdfs reader once done
Merge branch 'yingdac-evaluators-checking-back-in' into reef-bridge