Ditch the dialogs, favor passing options instead.

I've decided to ditch the dialogs. Main changes.

1. No more asking things.
2. The `init` flag is now a subcommand `octopress deploy init <METHOD>`
3. The `init` subcommand now has a `--force` flag to force overwriting existing configurations
4. No longer offers to add configs to .gitignore, but still bugs you to do it for S3.
5. No way to append to the .gitignore file for you.

The only change that makes me a bit sad is that people have to edit their .gitignore files themselves. But it's probably better that way.