Add support for square bracket shorthand lists
Add test for shorthand output
EMR: terminate-clusters initial commit; Rename job-flow-id(s) argument to cluster-id(s)
EMR: Added describe-cluster command.
EMR: Add add-tags command.
EMR: Add modify-cluster-attributes command.
EMR: Add install-applications command.
EMR: Added constants; Fixed minor typo in add-tags command.
EMR: Implemented create-cluster, add-steps, add-tags, create-default-roles, create-hbase-backup, disable-hbase-backup, schedule-hbase-backup, add-instacne-groups, ssh, socks, put, get, install-applications commands. Refactored describe-cluster. Added unit tests and examples.

EMR: Implemented add-steps.

EMR: Added create-hbase-backup and schedule-hbase-backup

EMR: Add --restore-from-hbase-backup option in create-cluster command.

EMR: Implemented disable-hbase-backup command.

EMR: Implemented create-default-roles.

EMR: Added unit tests for add-steps; Fixed bugs in create-cluster; Code cleaned up.

EMR: Refactored describe-cluster command to include bootstrap actions and instance-groups in the output.

EMR: Added create-cluster unit tests; Minor bug fix.

EMR: Add argument schema

EMR:  Modified help texts and examples for: add-steps, create-default-roles, describe-cluster and add-tags. Removed set-visible-to-all-users and set-termination-protection commands.

EMR: Minor bug fix in adding-steps; Integrated with CLI parser.

EMR create-cluster: Integrates --instance-groups, --ec2-attributes,--applications,--steps and --bootstrap-actions options.

EMR: Adds help texts and examples for create-cluster command.

EMR: Updated add-steps  unit tests

EMR: Modified install-applications and output of create-default-roles and added unit tests.

EMR: Added AddInstanceGroups command.

EMR: Added ssh, socks, put and get commands.

EMR: Add unit tests for create-cluster
EMR: Updated  help text.
EMR: Fix putty key file format bug.Add feature to use executable based on key format if both ssh and putty are available.
EMR: Added validation for applications.
EMR: Add tests for reading custom argument schema input from json.
EMR: Adds Properties field for --steps option.
EMR: Fixed unit tests and formatting.
EMR: Made changes required for Python 2.6 and 3.3 in Mac OS. Fixed bugs in ssh.py
EMR: Minor code restructure. Refactored helper methods, add-tags and create-default-roles.

Moved commands into separate modules.
Moved CLIOperationCaller and invoke to emrutils.py
Deleted AddTags custom command and modified tags argument for add-tags.
Refactored create-default-roles.
EMR: Updated help texts and examples.
EMR: Modified describe-cluster to fetch all results. Used FROM_FILE to read example files for EMR commands. Fixed unit tests.
EMR: Set create-cluster --ami-version as a required option and add regex check. Updated help text. Updated create-cluster unit tests.