* 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
Merge branch 'master' into sergiym_yarn_classpath_fix

Conflicts:
	reef-runtime-hdinsight/src/main/java/com/microsoft/reef/runtime/hdinsight/client/HDInsightJobSubmissionHandler.java