Added the beginnings of a CLI for HDI
Commit before using HTTPClient
 * Some progress towards the command line
Merge branch 'master' of https://github.com/Microsoft-CISL/REEF into weimer_hdicli

Conflicts:
	reef-runtime-hdinsight/src/main/java/com/microsoft/reef/runtime/hdinsight/client/yarnrest/HDInsightInstance.java
Merge branch 'master' of https://github.com/Microsoft-CISL/REEF into weimer_hdicli
Renamed HDICommandLine to HDICLI to resolve a build error about file naming...
Merge branch 'master' of https://github.com/Microsoft-CISL/REEF into weimer_hdicli
Log fetching now works
Moved the CLI code to reef-runtime-hdinsight
Documentation updates
Merge pull request #894 from Microsoft-CISL/weimer_hdicli

A CLI for YARN's REST API
Merge branch 'master' of https://github.com/Microsoft-CISL/REEF into shravan_groupcomm_interfaces