update
Added FileUtils.java which contains a single method that writes a string to a file with buffering.

Used that method in YarnContainerManager.java
fixes in ClientJobStatusHandler: try to send init before handling messages; bugfix: infinite loop in byte[] event handler; fix the logging; refactor
fix the DriverRuntimeConfiguration: use hte right Clock StartTime handler
move sendInit() call to the right event handling method
added yarn killed logic
Merge branch 'weimer_FileUtils' into sergiym_client_job_status_init
update evaluator kill logic
update
update container request counter
Merge pull request #657 from Microsoft-CISL/weimer_FileUtils

Use buffered write in YarnContainerManager
make sure requestedContainerCount does not go below 0
minor fixes to the logging in YCM
fixes due to code review: remove guava dependency; minor cosmetic fixes
Merge pull request #658 from Microsoft-CISL/sergiym_client_job_status_init

Handle Evaluators killed by YARN
Merge branch 'master' of https://github.com/Microsoft-CISL/REEF into weimer_alternative_to_656