harmonic init/config: list available preprocessors instead of asking user to type

[UltCombo]

Prompting from a list of choices, such as Inquirer.js's List prompt, would be useful for the preprocessor selection.

I guess co-prompt does not support this feature.

[jaydson]

That's an great idea.
We can do this for any kind of list choices, like template, for example.
We need to check how inquirer will behave together with co-prompt and vice-versa.

[UltCombo]

Inquirer is very versatile, though it is mostly asynchronous (no yielding).
Not sure if it would be smart to have two dependencies that do basically the same thing.
So yeah, we'd most likely have to rewrite the current prompts in order to migrate to Inquirer. Though it shouldn't be too hard of a task either.