Introducing the StreamingCodec interface

Also includes some clean up and some utils
Create a FailedEvaluator when the Evaluator is killed by the resource manager

This closes #999
Merge pull request #1000 from Microsoft-CISL/weimer_999

Create a FailedEvaluator when the Evaluator is killed by the resource manager
address PR comment
Merge branch 'master' of https://github.com/Microsoft-CISL/REEF into shravan_ng_groupcomm_1
Merge pull request #984 from Microsoft-CISL/shravan_ng_groupcomm_1

Introducing the StreamingCodec interface
Merge pull request #1012 from Microsoft-CISL/yingdac-speed-up-dll-extract-and-load-time

Improved performance when loading DLLs for the .NET Driver
Minor cosmetic changes
Merge remote-tracking branch 'origin' into yingdac-fix-yarn-conatainer-allocation
Merge remote-tracking branch 'origin/yingdac-fix-yarn-conatainer-allocation' into yingdac-fix-yarn-conatainer-allocation
Merge pull request #1011 from Microsoft-CISL/yingdac-fix-yarn-conatainer-allocation

Improved Container Allocation in the YARN Runtime
Removing group communication
Merge pull request #1013 from Microsoft-CISL/shravan_remove_groupcomm

Removing group communication
Merge remote-tracking branch 'origin' into yingdac-release-unwanted-container
release unexpected container as a hot fix for duplicated container allocation
Merge branch 'yingdac-release-unwanted-container' into reef-bridge-release
Merge pull request #1014 from Microsoft-CISL/yingdac-release-unwanted-container

release unwanted container
Merge remote-tracking branch 'origin' into reef-bridge-release