adds support for a 'defaults' YAML file to the hanlon_init script
adding in option to pass in override parameters as a JSON string
Moved code block that catches the case where both the defaults file and the
json defaults flags were set (outputting a sensible error and exiting); without
this change that edge case was not caught
Catches parse errors that are thrown when an invalid option is included in the
command line arguments for the hanlon_init script
Changing puts commands to print commands in the ERROR and WARN outputs
Merge pull request #280 from tjmcs/tb/override-config-params

Fixes #231 (Add ability to override configuration parameters)