Added long-args and refactored script
Added long-args and refactored script

- Added long args for each arg (Thanks: http://mywiki.wooledge.org/BashFAQ/035)
- Refactored code into functions (Thanks: https://github.com/progrium/bashstyle and http://kvz.io/blog/2013/11/21/bash-best-practices/ and http://www.shellcheck.net/)
- Added increasing verbosity
cameronoxley/Newman-to-Slack