Set better defaults & accept default w/ enter key

Hi there!

I'm excited to dig into this tool but today when I went to set it up I ran into a little bit of friction. Hopefully this pull request is agreeable and the friction can be removed for future users.

The standard Unix convention for CLI prompting is that the upper case character be the default option without needing to specify any input (pressing enter will choose the default option for the user). This pull request allows for that to work. I also changed some of the defaults to what seem to me to be a more straightforward setup for attracting more new users. Let me know if our thinking doesn't mesh on this and I'm happy to discuss!

Thanks much,
Jon