Show cluster name in status command.
Semi
Merge pull request #168 from aholmberg/status-report-cluster

Show cluster name in status command.
Add yaml_merge function to common.py
Add argument to pass in yaml file to updateconf
Merge custom yaml into each node's cassandra.yaml
Validate yaml_file path exists
Add test for yaml_merge
Improve yaml_merge

Was unnecessarily complex. Was not merging items that were in
primary but not in secondary
Merge pull request #172 from pcmanus/updateconf_yaml

Updateconf yaml