[origin-dev-ui-160] Add support to clone app on create: 'rhc create-app <clone> --from <existing>'

https://trello.com/c/RtkqtAop/160-a-user-can-upgrade-or-clone-an-application-via-rhc-and-the-snapshot-feature
Bug 1071240 - fixes app cloning with downloadable cartridges
Fixes 1071814 - exception when creating app with gear size
Adding feature tests for create-app from