Leveraging the core “Display Site Title and Tagline” Customizer option with Site Logo
Update (4/18/17): While this article is technically accurate, there’s a better way of doing this. Stay tuned for an update.
Update (4/18/18): (Almost exactly a year later) Due to a UX issue I will be pulling the content of this post to avoid spreading bad information. Will be resurrected with accurate information when I have the chance.