Add favicon

[Kikobeats]

In all sites that I run docpress favicon is missing!

What about add this functionality? 😄

Related: https://github.com/arccoza/metalsmith-favicons

[rstacruz]

What would be the favicon tho?

[knownasilya]

The docpress logo?

[rstacruz]

maybe have a default favicon, then allow the user to add docs/favicon.png to override it. hmm.