Add hints

[jasonaowen]

It would be nice to show some hints for a person, so if you aren't sure you're not just faced with an empty text box.

I was imagining something like "It's one of these four names", and if you click hint again "It's one of these two names".

[jasonaowen]

Or:

Have you thought about maybe providing an array of names and matching to a face or the opposite matching faces to a name?
-@stanzheng

[jasonaowen]

Or:
The first hint could show the length of the name, and each additional hint could show a letter, kinda hangman-style.

[jasonaowen]

@botwhytho implemented this in #16. Thank you!