Fix cluster cleanup
Fix cluster cleanup

- merge create & wait functions to a single while loop
- have create clean up after itself so testBuilder doesn't have to

dcos/dcos-cli,kensipe/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli,dcos/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,kensipe/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli