* Added support for killing applications to `HDInsightInstance`
  * Added support for reading HDInsight configurations from files and from a file referenced by an environment variable
  * Updated HelloHDInsight to use the environment variable to find its configuration file
minor formatting fixes
Fixing #893

Adding ResourceLaunch & ResourceRelease Handlers into the
DriverSingletons.
RunningTask.close() is now idempotent

This closes #895 by making `RunningTask.close()` idempotent. It also changes `RunningTask.close(byte[])` to throw an Exception when the Task is no longer in state `RUNNING`
Merge pull request #896 from Microsoft-CISL/weimer_895

RunningTask.close() is now idempotent
Merge pull request #897 from Microsoft-CISL/shravanmn_893

Fixing #893
Adding fixes from tr_fix
Merge remote-tracking branch 'origin/master' into shravan_groupcomm_interfaces
Baseline consistent across runs

Also fixed an issue in FailedTaskHandler
small changes in Broadcast demo settings
allreduce
Handle failures in allreduce
allreduce with new task addition and failed task deletion
update allreduce to merge code from shravan_groupcomm_interfaces
improve hyper cube topology control and fix bugs in handling source dead/add events
merge code from shravan_groupcomm_interfaces