* moved secrets config template to config directory
* updated new default file location for secrets.cfg
* added ConfigObject class
* added template for cluster config file
* updated .gitignore to include cluster.yaml
* updated cluster.yaml.template to include more fields
* added read_config_file method to ConfigObject, modified cluster_create.py to use cluster.yaml configuration by default
* added pyyaml to requirements.txt
* added documentation for cluster.yaml config file
* added constant for default cluster.yaml location
* changed secrets.cfg to secrets.yaml, added SecretsConfig object
* removed secrets.cfg.template
* improved error messages for bad secrets.yaml config
* changed config/ directory to .thunderbolt/
* remove old unused code
* removed unncessary ignored file
* renamed configuration class to ClusterConfig and added merge method with error checking
* collapsed cluster.yaml file
* updated cluster.yaml.template to new collapsed format
* better descriptions of cluster config settings
* added error checking to cluster config settings
* added back accidentally removed code
* removed template for cluster.yaml, added cluster.yaml
* renamed .thunderbolt/ to config/, added defaults for cluster.yaml
* fixed typo in secrets.yaml.template
* added .thunderbolt/ directory to .gitignore
* fixed bug when adding user with ssh_key
* code cleanup
* updated docs
* removed redundant docs, added instructions to secrets.yaml.template
* fixed typo
* refactored read_config_file method and changed default cluster id
* removed unnecessary ignored file
* changed format for cluster.yaml instructions
* added back docker-repo support
* refactored merge and merge_dict methods
Timothee Guerin
Jacob Freck