Don't mess w/ a response that is directly passed in

This fixes a regression where zenflow would not accept the branch name directly in the 'zenflow feature start branch_name_here' command.
Allow underscores here too
Move default option to lower case to follow convention
Convert Ruby 1.8 hash syntax to 1.9

- 1.8 is EOL
- This project already had a mix of both anyway
- The has_syntax gem was used after manually converting a few files and 
deciding: "awe hell nah"