WIP: API Clean Up

Overall there are a few things that I'd like to address in this update:

- [ ] Bump when.js to version 3.0 and bind the context to the whole chain
- [ ] Clean up the API by dropping `url` convention for a `template` argument
- [ ] Allow API to determine whether a url or a local path was passed as an argument, and act accordingly
- [ ] #12 - Replace flatiron/prompt with Inquirer.js 
- [ ] Expose a `sprout.configure(<path>)` function which is chainable with others like `.add()` and `.remove()` This is mostly helpful with tests, but could have some real world implications as well